In this paper we study the chaos synchronization of a new Lü chaotic system containing constants via three methods, i.e., state observer, active control method, and backstepping method. Based on the above three methods, the we design an adaptive controller according to the Lyapunov stability theory which proves that the controller can well realize the asymptotical synchronization between two identical systems. Through numerical simulation, we further verify the effectiveness and the advantage of the above three synchronization methods. The synchronization method based on state observer is believed to be more flexible and efficient through the comparative analysis of three kinds of synchronization methods.