Reason: After the Opium War, China gradually became a semi-colonial and semi-feudal society. China people's opposition to the Taiping Heavenly Kingdom movement led by the peasant class was finally stifled by the reactionary forces at home and abroad, and it did not change the nature of China's semi-colonial and semi-feudal society. The Westernization Movement of the landlord class did not make China rich and strong. Due to the weakness and compromise of the bourgeoisie, the Reform Movement of 1898 and the Revolution of 1911 failed. The nature of China's semi-colonial and semi-feudal society has not changed, and the spread of Marxism in China was in the late period of the New Culture Movement. External cause: After the victory of the October Revolution, the advanced intellectuals in China turned their hope of saving the country and the people from Europe to Russia, and no longer regarded the bourgeois republic as their only ideal. 1 Began to observe the world with a new worldview and methodology, while paying attention to the power of the working class. The victory of the October Revolution embodies the scientific nature of Marxism, and at the same time, the internal and external policies of the Soviet Russian government after the October Revolution touched the people of China. Internal causes: 1 the strength of the working class, the pertinence of Marxism to China's specific national conditions, and the compatibility of Marxism with China's traditional culture.