The theory of surplus value by Marx unlocks the secret of exploitation."Surplus"provides a cognitive perspective,from which Marcuse elaborates on surplus repression,Žižek proposes surplus obedience,Reich establishes the sociology of sex economy,and Lacan illustrates the surplus jouissance as the motivation of desire.In Lacan's view,jouissance is a bridge between surplus value in the Symbolic and the surplus jouissance in the Real.From the workers,capitalists exploit not only the wealth embodied in surplus value but also jouissance and knowledge.With this knowledge,a symbolic network of rationalization and legalization of exploitation and oppression has been constructed.Identifying with this symbolic order,workers can only get the surplus jouissance built on pain.Through the theory of surplus value,Marx profoundly reveals the essence of capitalism's exploitation;Lacan's theory of surplus jouissance exposes the most secret underlying logic of the legitimacy and rationality of the construction of capitalist symbolic order.