British just want to reverse the trade deficit, the solution they tried was to smuggle and dumping opium to China. Before the First Opium War, Qing Empire only opened one city for international trade, which was Canton(Guangzhou) City. After the First Opium War, Britain forced Qing Empire signed the Sino-British Treaty of Nanking(Nanjing), opened Fuzhou, Xiamen, Ningbo, and Shanghai for international trade. China began to transform into semi-colonial and semi-feudal society. After the Second Opium War, Britian, Russia and France forced Qing Empire signed The Treaty of Beijing. Russia forced Qing signed Treaty of Aigun. Britain, Russia, France, and USA forced Qing to sign the Treaty of Tianjin. After the Eight-Power Allied Forces war of aggression against China, USA, British Empire, Japan, Russia, French Third Republic, German, Italy, Netherlands, Spain, Belgium, and Austro-Hungarian Empire forced Qing Government signed the Boxer Protocol, and the Qing Government became their ruling representative. China became semi-colonial and semi-feudal society completely. The contradiction between Chinese people and the colonial foreign invaders became the main contradiction of Chinese society.