Abstract: Based on relevant historical literature, this paper explores the 2nd National Congress of CPC in the background of the Sinolization of Marxism. The result shows that this congress not only made a detailed analysis of China's national conditions and characteristics of the era, but also gave proper answers to such questions as the nature, steps, targets, motives, and prospects of China's revolution. It made an important contribution to the Sinolization of Marxism, and was a crucial link of the first historical leap in the Sinolization of Marxism.