Abstract. Electric power systems are one of nonlinear, multidimensional, dynamic and large scale systems. Once power systems lose stability, it would result in the consequence is very serious. With excitation control for multi-machine power system nonlinear model in this article, a series of stability control problems are studied by means of the improved backstepping methods, including excitation control. The nonlinear adaptive robust controller which can stabilize the system has been designed. The concise design method and excellent design strategy make the designed corresponding control scheme own extensive adaptability, which effectively improve the maintain system power angle and voltage stability.