Abstract: Marx and Engels' thinking about the Communists was closely linked with the proletariat, and they were regarded as the most vivid and advanced representatives of the proletariat. Among them, the scientific attitude of seeking truth from facts is the political character of the Communists, the spirit of selfless and fearless revolutionary struggle is the spiritual motivation of the Communists, and the practical appeal of the Communists is to arm their minds with scientific theories. Standing in the position of the proletariat, the communists' lifelong mission is to insist on seeking interests for the vast majority of people, endeavor to construct the ideology of the proletariat, and establish a new communist society without exploitation and no oppression. Chinese Communists follow the view that "Communists are representatives of the proletariat". Pioneer model has always been their bright characteristics, and they continuously develop the important character and mission of the Communist Party in the new era so that the theoretical character and important mission of the Communist Party constantly glow with vitality. It fully reflects the responsibility of the Communist Party of China as well as the inheritance and development of Marxist theories and theories.