Abstract: Only the theory of contribution is the truth among the theories of social justice;all other theories are wrong.However,none of them is completely wrong,for whatever wrong theory it is and no matter how wrong it is,it adapts certain principle in social justice that belongs to the theory of contribution or is deducted from it.Firstly,the equalism has the most principles on social justice,e.g.the basic rights are completely equal,the non-basic rights are equal in portion,and the  equal in chance and consequence (equal in politics and economy).Though these principles in the eyes of the equalists are not all deducted from the theory of contribution,they can be deducted from the theory of contribution and thus they belong to the category of contribution theory.Secondly,the theory of needs has the fewest principle;the only one principle in it is to distribute human right according to the basic needs.However,the nature of this principle is to distribute human rights according to the contribution to society,thus it also belongs to the category of the contribution theory.Lastly,the right principles of social justice by the theory of free justice are two equal principles,i.e.the complete equal in basic right and the non-basic rights are equal in portion;they belong to the category of contribution theory,either.Therefore,the theory of contribution includes all the right principles of social justice and is the truth of social justice.

Key words: contribution,demand, right, duty, principle of kindheartedness, principle of justice, principle of freedom