The Opium War of 1840 marked a turning point in Chinese history. From early in the 19th century, Britain started smuggling large quantities of opium into China, causing a great outflow of Chinese silver and grave economic disruption in China. In 1839, the Qing government sent Commissioner Lin Zexu to Guangdong to put into effect the prohibition on opium trafficking. When, in an effort to protect its opium trade, Britain initiated the First Opium War in 1840, the Chinese people rose in armed struggle against the invaders under the leadership of Lin Zexu and other patriotic generals. But the corrupt and incompetent Qing government capitulated to the foreign invaders time and again, and finally signed the Treaty of Nanjing with Britain, a treaty of national betrayal and humiliation. From then on, China was reduced to a semi-colonial and semi-feudal country.

After the Opium War, Britain, the United States, France, Russia and Japan forced the Qing government to sign various unequal treaties, seized "concessions" and divided China into "spheres of influence." To oppose the twin evils of feudal oppression and foreign aggression, the Chinese people waged heroic struggles, with many national heroes coming to the fore. The Revolution of the Taiping Heavenly Kingdom in 1851, led by Hong Xiuquan, was the largest peasant uprising in modern Chinese history. The Revolution of 1911, a bourgeois-democratic revolution led by Dr. Sun Yat-sen, ended the rule of the Qing Dynasty. The monarchical system that had been in place in China for more than 2,000 years was discarded with the founding of the provisional government of the Republic of China. The Revolution of 1911 is of great significance in modern Chinese history. But the fruits of victory were soon compromised by concessions on the part of the Chinese bourgeoisie, and the country entered a period of domination by the Northern Warlords headed by Yuan Shikai. The people lived in an abyss of misery in this period.