The anniversary of the founding of the Communist Party of China is on July 1st every year. After the success of the October Revolution in Russia in 1917, Marxism quickly spread throughout China. After the May Fourth patriotic movement, the earliest revolutionaries who accepted Marxism-Leninism, such as Li Dazhao, Chen Duxiu, Mao Zedong, Dong Biwu, and others, established communist groups in various places to promote Marxism-Leninism and carry out workers' movements. With active assistance from the Comintern led by Lenin, representatives from various communist groups convened in Shanghai in July 1921 for the First National Congress of the Communist Party of China. Later, due to being discovered by imperialist spies, the meeting was transferred to a boat on Nanhu Lake in Jiaxing, Zhejiang Province, to continue. Attendees included Li Da, Li Hanjun, Zhang Guotao, Liu Renjing, Dong Biwu, Chen Tanqiu, Mao Zedong, He Shuheng, Wang Jinmei, Deng Enming, Chen Gongbo, Bao Huiseng, Zhou Fohai, totaling thirteen people, representing fifty-seven party members nationwide. There were also representatives from the Comintern, Maring, and the Red International of Labor Unions, Nikolsky. The congress passed the party's constitution, elected Chen Duxiu as General Secretary, and announced the establishment of the Communist Party of China. From then on, a completely new-style, unified working-class party with communism as its goal and Marxism-Leninism as its guiding principle appeared in China. The birth of the Communist Party of China opened up a new era in Chinese historical development and brought about a complete transformation in the face of the Chinese revolution. During the War of Resistance against Japan, due to difficult conditions, the exact date of the "First Congress" could not be recorded. Therefore, in 1941, the Central Committee decided to set July 1st, the first day of July 1921, as the party's birthday and commemoration day.