He -wanted to- and there was a window of opportunity in the early 1950s to do so. the big factor as to why he didn't was because of the Korean War. Before the Korean war the PLA was deployed in the south of the country in preparation to invade Taiwan, but because of the Korean War it shifted north to fight in Korea instead.

Because of the Korean War the US also took the hard-line against the PRC in East Asia whereas before it had no special interest in Taiwan. The year after the Korean War ended (1954) the PRC attempted to once again force the issue, with premier Zhou Enlai declaring that the PRC intended on taking Taiwan and significant artillery bombardment commenced on both Kinmen and the Matsu Islands. In response, the secretary of state Dulles publically stated that the US was willing to use nuclear weapons to defend Taiwan. The US congress also passed the Formosa act, authorizing the usage of force to defend the island. The PRC went to the negotiation tables the following year. While there was to be another Taiwan crisis in 1958, the PRC was never able to force the issue.

/u/DeSoulis went into the political side so I'll go into the strategic bits.

Taiwan looks small and diminiuitive on maps, especially when compared to the juggernaut of the People's Republic of China.

But one of the main reasons the nationalists moved to Taiwan was because of strategic security the location provided. The PRC navy at the time had almost zero open sea naval capability - much of it was river and coastal boats.

The other important thing to remember, amphibious landings are a highly complex combined arms operation that few nations, even today, can pull off. Opposed amphibious landings, that is, landing on a defended beach under fire, is even more difficult and inherently an incredibly risky military maneuver.

The PRC naval forces in the 1950s and 1960s lacked two major things that they needed for any theoretical scenario that pitted them against Taiwan.

1) Lack of heavy duty warships

What cruisers and missile frigates the PRC did have was either bought direct from the USSR or received massive amounts of help in construction and development by the USSR. But they did not have nearly enough for the ideal mission in the minds of PRC military planners of the time, a naval blockade of Taiwan to force capitulation.

They also did not have nearly enough firepower concentrated in their cruisers and escort ships to provide support fire in the case of the less ideal mission, a full out amphibious invasion on Taiwan.

This is not even considering the fact that the PRC navy might have to face off against US navy ships if they did invade Taiwan in the 1950s and 1960s.

2) Lack of amphibious landers/transports in general

The PRC severely lacked amphibious assault vehicles that could be used to send troops into an opposed landing. Even with ideal weather conditions as well as lots of air and naval support, World War 2 showed that opposed landings in modern warfare were brutal not just in combat but in logistics as well.

They were not a simple operation to pull off.

And the casualties were often high very high.

People often think have an image of PRC military doctrine as just sending waves after waves of men in near suicidal attacks until they overwhelm the enemy. This is a stereotype and commanders often considered combat casualties when deciding what to do. That being said, taking objectives 'at all costs' was also valid.

But in a Taiwan invasion scenario, they don't even have the luxury of considering throwing dead bodies at the problem. Any operation against Taiwan involved a massive amount of military intelligence and a command structure able to digest and act on it in a reasonable amount of time, supplying naval and land forces far away from PRC supply lines, round the clock air operations, and communications between thousands of units, 3 different command structures, etc.

The sheer logistics of amphibious landings are often overlooked but in reality, they are incredibly monumental operations when conducted in scale and only a select few military forces have ever been able to properly conduct them throughout history. It's never as simple as 'let's land 10,000 troops here'.

The logistics here were further compounded by the fact that much of the Taiwanese coastline is not suitable for a large amphibious landing. This problem is further compounded by the fact that the Taiwanese tide is considered very difficult to work with in terms of a landing.

Anyways, because of the limited number of transports (Chinese military planners expected that in case of an actual invasion of Taiwan, they would likely need to requisition every civilian boat they could to supplement military vessels), any theoretical landing operation was very risky.

Especially if US air assets/naval assets intervened.

Taiwan's interdiction ability was limited but US forces would be more than a match for a force steaming towards Taiwan.

Chinese military planners worried that staging areas in Nanjing and Guangdong would be subject to US bombing while Chinese transports would be sunk with their landing troops before they could even reach Taiwan, resulting in tens of thousands of casualties before even reaching Taiwanese soil.

These two issues were never really 'fixed'.

While PRC naval forces continued to expand and develop, they never had enough resources where they could comfortably assure officials of the success of a landing scenario, which meant in case of a Taiwanese conflict, the ideal was to enforce a blockade of Taiwan in the ocean while keeping the US out of the conflict in the political arena.

The PRC instead invested heavily into missile and SAM technology that allowed them to increase the amount of firepower they could bring down on Taiwan land and airspace.

This arguably helped a great deal, especially the SAMs as it would help them in the fight for air superiority in and along the invasion corridor, which would have been essential to keep casualties of troops and transports en route to a minimum.

But more importantly, long range missiles allowed the PRC to threaten Taiwan without having to risk a blockade or invasion.

Taiwan's greatest asset strategically was the tiny strip of water between it and the mainland.

If you have any more questions I'd be happy to answer them to the best of my ability. Cheers!

In Henry Kissinger's book "On China" he hashed out the tricky manoeuvrings of Mao, who would wait for Khrushchev's visits to China before shelling the Kinmen and the Matsu Islands, in the straits between mainland China and Taiwan. Although bombarding those islands seemed more symbolic than strategic, Mao's timing of shelling right after different visits by Khrushchev led the US to believe that the Soviets were influencing Chinese foreign policy, and the international communist movement as a whole. Kissinger surmised that Mao did this to redirect US/Western pressure away from Beijing and towards Moscow.

I'd like to point out the factors that did exist in the successful PRC invasion of the island of the ROC-held Hainan in early 1950 that did not exist in considering a possible PRC invasion of Taiwan during the same period:

• There was a relatively large and organized Communist armed force already in Hainan that did not exist in Taiwan. The Communists in Hainan, which was occupied by the Japanese from 1939-1945, conducted guerrilla operations against the occupying Japanese, who were hated by the population for killing 1/3 of males on the island. In Taiwan, on the other hand, most of the population really didn't mind the Japanese so much - and a non-negligible amount of males there actually served in the Japanese armed forces in the war. So there was not an effective Communist guerrilla force in Taiwan to support an invading force, as there was in Hainan.
• The Hainan operation occurred in the months immediately prior to the Korean War, when there was a much lower possibility of US intervention. In fact, a few months earlier in January 1950, US President Truman had said that the US would stop intervening in the Chinese Civil War, although it still recognized the ROC as China's legitimate government. These months in between January 1950 and the start of the Korean War would be as good as conditions would get for a PRC naval assault.
• The Taiwan strait is wider across and with more difficult conditions for landing than the body of water between Hainan and the Guangzhou mainland, which was in fact narrow enough that land-based artillery from the mainland could help somewhat neutralize the effectiveness of Taiwanese naval units operating there.
• Thanks to the infrastructure work of the Japanese during their long occupation of Taiwan, Taiwan was just much more developed and thus strategically important than Hainan. The ROC would devote all its resources to the defense of Taiwan in a way that they wouldn't to the defense of Hainan.