This paper studies the realization of anti-synchronization of hyperchaotic Chen system by three methods, i.e., the active control method, global control method and variable replacement method. The methods are proved valid by Lyapunov stability theory and numerical calculation of the largest Lyapunov exponent. The variable replacement method is more practical because it can anti-synchronize drive system and response system by transmitting one single signal. Numerical simulations show the effectiveness of the three methods.