The concept of “labor” is a basic concept in the theoretical system of Marxism. In Economic and Philosophic Manuscripts of 1844 , Marx made the first exploration of labor issues in the sense of philosophy and economics by historically transforming the concepts of British classical political economy, Hegel and Feuerbach, clarifying the essence of human beings in labor, and exploring the key to correctly answering the “mystery of history”. In the later Das Kapital and its manuscripts, on the basis of scientifically grasping the objective laws of social and historical development, Marx placed labor in capitalist production, and endowed the concept of labor with a new connotation of political economics criticism.The duality oflabor reveals that labor under the logic of capital is wage labor, thus discovering the source of surplus value.When comparing two works, some western Marxists think that Marx’s research on the concept of labor has a “rupture” at the cognitive level, contrasting the alienation logic of Marx’s early humanism with the scientific thinking starting from the realistic capitalist criticism in the mature period.But at its root, from the Economic and Philosophic Manuscripts of 1844 to Das Kapital , the fundamental goal of Marx has always been to sublate the alienated state of labor to human beings based on labor liberation and realize the free and comprehensive development of human beings.From the perspective of ontology, Marx understood that the basis of “solving the problem of human existence” lies in economic reality. Therefore, Marx’s research on the concept of labor realized the “sublimation” from speculative philosophy to scientific demonstration,reflecting the continuity of the development of Marx’s thought and plays a decisive role in the establishment of historical materialism and the realization of human liberation.