Fuzzy control is a model-free linguistic control (if-then rules), which is easy to understand and provides nonlinear controllers for nonlinear systems. In recent years, some fuzzy controllers with an adaptive mechanism for unknown systems have been studied. In these studies, the parameters of a fuzzy controller are adjusted by some experience of human opereators or adaptive lows with some if-then rules. But the stability of the control system which is constructed by the plant and the fuzzy controller has not been analysed in most of these studies In this paper, we propose a class of Model Reference Adaptive Fuzzy Controllers for nonlinear systems. This class of controllers are the fuzzy controllers with the structure of the direct adaptive control system which can directly stabilize tracking error e. Finally, we derive the stability conditions (the adaptive laws) for the fuzzy controller for nonlinear systems by taking quadratic parameter error φ_i as the Lyapunov function V.