Marx did not systematically express a theory of justice. However,when we interpret historical materialism as accommodating determinism and activism,and hence as accommodating a normative theory,we can construct a Marxist theory of justice based on conditions in socialist society anticipated by Marx. Because it is based on the historical principle of moral norms,this theory transcends Kant’s moral philosophy,which is the completion of modern moral philosophy. Because it tries to adjust the unequal distribution of goods based on the principle of human beings’ free development,this theory is intuitively more natural than and hence superior to Rawls’ s principles of justice. In addition,this theory is established in modern social life,making it more reasonable and feasible than the communitarian moral philosophy which tries to return to ancient times and therefore falls into anachronism.