<正> Based on active control theory,anti-synchronization between two different hyperchaotic systems is inves-tigated.The sufficient conditions for achieving anti-synchronization of two different hyperchaotic systems are derived.Moreover,numerical simulations are presented for hyperchaotic Lorenz-Chen system,hyperchaotic Lorenz-Lü system,and hyperchaotic Chen-Lü system to verify the effectiveness and feasibility of the proposed anti-synchronization scheme.