Abstract: The Sixth Plenary Session of the 19th CPC Central Committee comprehensively summarized the major achievements and historical experience of the CPC's century-old struggle，and systematically answered the major questions of “why it is necessary” and “why CPC is qualified” to summarize the historical experience of the century-old struggle. From the historical dimension，it is the CPC tradition to sum up experience at major historical moments and unite and lead the whole Party to look forward. From a practical perspective，summarizing historical experience is necessary to develop socialism with Chinese characteristics and build a modern socialist country，to implement the “two safeguards” and ensure that the whole Party is in step with each other，and to realize the great rejuvenation of the Chinese nation. From the dimension of the Party's development and construction，political and ideological unity of the whole Party is the basis for successfully summarizing the historical experience of the Party's century-old struggle，and adherence to historical materialism，and correct Party history and grand history view is the basic methodology for the Party to successfully summarize the historical experience of the Party's century-old struggle.

Key words: the Communist Party of China, a hundred years of struggle, historical experience, historical tradition, the Party's resolution