The Communist Party of China (CPC) was founded in the 1920s. It was the natural outcome of developments in Chinese society and the Chinese people's revolutionary struggle. It resulted from the integration of Marxism-Leninism with Chinese workers' movement.

In early 1920, Li Dazhao (1889-1927) and Chen Duxiu (1879-1942), two key figures in founding the CPC, started making preparations in Beijing and Shanghai to found a communist political party in China. In Peking University in March, Li Dazhao set up a society for the study of Marxist theories. This was the first such body to be established in China. In Shanghai in May, Chen Duxiu organized a society for the study of Marxism. Based on these groups, Chen and others decided to found a communist party organization in June. When Chen consulted Li about the name of the new organization, Li suggested "Communist Party" and Chen fully agreed.

A communist organization was formally set up in Shanghai in August 1920, under the name of the "Chinese Communist Party." This was China's first communist party organization. A similar body in Beijing was founded in October, called the "communist group." Following these, similar early-period communist organizations were set up in Wuhan, Changsha, Ji'nan, Guangzhou and other places across China, and among progressive overseas students and Chinese expatriates in Japan and Europe. These organizations helped spread Marxism and integrate Marxism with the Chinese workers' movement, and paved the way for the formal founding of the CPC.

On July 23, 1921, the First National Congress of the Communist Party of China was convened in Shanghai. Following harassment by external authorities, the delegates moved to Jiaxing in Zhejiang, a neighboring province of Shanghai, to hold their final session on a sightseeing boat on the Nanhu Lake.

The delegates to the congress were: Li Da (1890-1966), Li Hanjun (1890-1927), Dong Biwu (1886-1975), Chen Tanqiu (1896-1943), Mao Zedong, He Shuheng (1876-1935), Wang Jinmei (1898-1925), Deng Enming (1901-1931), Zhang Guotao (1897-1979), Liu Renjing (1902-1987), Chen Gongbo (1892-1946) and Zhou Fohai (1897-1948). Bao Huiseng (1894-1979) was a delegate dispatched by Chen Duxiu. They represented more than 50 Party members across the country. Two representatives of the Communist International (the Comintern), identified as "G. Maring (1883-1942)" and "Nikolsky (1889-1938)," attended the meeting as observers.

The delegates decided that the name of the new party would be the "Communist Party of China," and adopted the Program of the Communist Party of China, which contained the following provisions: The revolutionary army and the proletariat must work together to overthrow the power of the capitalist class; establish and maintain the dictatorship of the proletariat until the end of class struggle or the elimination of classes; abolish private ownership of capitalists; confiscate the machines, land, factories and semi-finished products and other means of production to be owned by the public; and ally the Party with the Third International (another name for the Communist International).

The Party's program affirmed the commitment to organizing the workers, peasants and soldiers, and set the Party's political goal as to undertake social revolution. The program contained provisions similar to those in a party constitution, as well as principles such as democratic centralism and Party discipline.

The congress passed the Party's first resolution, and defined leading the workers' movement as its central task with specific rules about how to organize and publicize the movement.

The congress elected a Central Bureau as the CPC's provisional leadership body, with Chen Duxiu serving as secretary, Zhang Guotao in charge of organizational work, and Li Da, publicity work.

This represented the formal establishment of the CPC. Thus, in a backward country with a long history, a unified political party of an entirely new type emerged, the only party that represented the proletariat and took Marxism-Leninism as its guide and socialism and communism as its goal. This was an epoch-making event in China's history – the culmination of social progress and revolutionary development in modern China. With the arrival of the Communist Party of China, the Chinese revolution took on a brand-new image.