Abstract: The present paper discusses the fine tradition and style work of the Communist Party of China in the following five aspects.Investigation and study is the scientific way in which MarxismLeninism was established，the trump card that guarantees the victory of Chinese revolution and socialism construction，the theoretical source that promotes reform and opening，and the fundament that ensures the leapfrog development and that keeps the Party flourishing.Therefore，the author emphasizes that the fine tradition and style of work of seeking truth from facts，investigation and study are the fundamental approaches we should always adapt for the sustainable and scientific development of our Party.

Key words: investigation and study, MarxismLeninism, fine tradition, the 90th anniversary of the Communist Party of China