Abstract: Based on theory of criticizing the legal legitimacy of western traditional law,Marx established the legal legitimacy theory on account of the philosophy of labor,emphasizing that legal legitimacy should be built on the basis of dialectical unity of subjective and objective,facts and values,individual and society,history and reality.The legitimacy of the law lies in that the law should not only reflect the actual situation of social material production and labor practices,but also conform to the subjective values of most social members,especially the workers who create material wealth.The law should not only fully protect the individual rights of social members,but also maintain social order,harmony and stability.Marxs theory of legal legitimacy is more reasonable than that of natural law school and positivist law school theories.

Key words: Marx, legal legitimacy, philosophy of labor