This paper presents a new adaptive excitation control for power system based on wavelet network. An application of wavelet networks to nonlinear excitation control of a power system is presented in this manuscript. A wavelet network is constructed as an alternative to a neural network to approximate a nonlinear system. Based on this wavelet network approximation, suitable adaptive control and appropriate parameter update algorithm are developed to force the nonlinear unknown power system to track a prescribed trajectory with desired dynamic performance. It is shown that the effects of approximation errors can be attenuated to a specific attenuation level using the proposed adaptive wavelet network control scheme. A single machine infinite bus system with uncertain fault location is presented to illustrate the proposed design procedure and exhibit its performance.