In this paper, We investigate the adaptive anti-synchronization in a unified hyperchaotic system with unknown parameters. First, according to the Lyapunov stability theory, We achieve an adaptive controller and show that the controller can make a unified hyperchaotic system with unknown parameters asymptotically stable at a fixed point. Second, by the adaptive anti-synchronization method, We design an adaptive anti-synchronous controller and thereby achieve the hyperchaotic system synchronization. Finally, numerical simulations show the effectiveness of the scheme.