The passive coordination control of excitation is studied and storage functions of the system are constructed using backstepping technique of the dissipativity and passivity theories for a single machine infinite bus system with static synchronous compensator (STATCOM). The coordinated controller for STATCOM and generator excitation which maintains system power angle and voltage stability is devised according to the characteristics of the coordinated passivity. Since the nonlinear characteristics of the system are fully utilized for the whole system without any linearizing method, the applicability of the control law can be ensured to the nonlinear system. The effectiveness and validity of the control law can be proved by the simulation results in this paper.