Commodity is not only the logical beginning for Marx to analyze capitalism，but also a pillar concept for Marx to construct his entire political economy.From things to commodities and from commodities to the commodity of labor power，Marx completed two "terminological revolutions" in the concept of commodity.Through the first "terminological revolution"，Marx overcame and clarified the defects and confusions of classical political economists on the understanding of commodities，and made theoretical preparations for establishing scientific labor value.Through the second "terminological revolution"，Marx made a precise analysis of the historical determination of labor power as a special commodity，laying a theoretical premise for revealing the secret of surplus value.