Marx and Engels believed that the pursuit of equality in class society was awakening with the development of material production.After the historical evolution of"substantive equality in the primitive community-pervasive formal equality-pervasive substantive equality",it finally developed into the socialist concept of equality,that is,the universal substantial equality pursued by the proletariat for the purpose of eliminating classes.Marx and Engels'theory of socialist equality not only criticizes the bias,neutrality and abstraction of capitalist equality,but also guides the proletarian dictatorship to gradually realize the harmony between man and nature,man and man,man and society in productivity,production relations,economic foundation and superstructure,absorbing the reasonable factors of capitalist legal equality.