The notion of labor takes an important place in Marxist theory. Adam Smith revealed that labor is the source of value, however, he only regards labor as a means to accumulate wealth, praises productive labor that can bring capital proliferation and devalues nonproductive labor. Hegel inherited Smith's notion of labor, and he put forward a brand-new proposition that labor creates man from a philosophical perspective, but the only labor he admits is abstract spiritual labor. Marx and Engels discarded Smith and Hegel's notions of labor, and linked labor with human nature, freedom, and liberation. By classifying labor into a series of paired categories, they posited the trajectory and essence of labor alienation, and pointed out that the active sublation of alienated labor is an inevitable link to human freedom. Marx and Engels’ notion of labor provides ideological resources for the capital narrative that breaks the mainstream of western society, and provides a theoretical basis for the formation of a socialist labor view with Chinese characteristics in the new era.