“The masses of individuals” are the forces of the proletarian and socialist revolution in Marx’s idea. Therefore, based on “realistic individuals” and through the criticism of the mass view of the old materialism, he constructed the logical premise of science of mass philosophy and opened the logical starting point of mass philosophy. And using the class and stratum analysis to divide the masses between the bourgeoisie and the proletariat, he found that “the people” is the fundamental force of revolution, thus endowing “the people” is the distinct implication of philosophical logic of the masses. Furthermore, around the thorough liberation of everyone, he promoted the mass philosophy to the logical destination in the exploration of “the association of free men”. In general, the mass philosophy in Marx’s thought contains the analysis path from “real individuals” to “people” and then to “free people association”. It has great academic value not only to further open up a new perspective of historical materialism, but also to highlight the concept of people as the subject in the new era through grasping this theoretical approach accurately.