Abstract: This paper analyzes the stability of an adaptive fuzzy control scheme which was presented by Li-Xin Wang in 1993,and proves two new results. First, the supervisory control is unnecessary in the sense of stability; second, the asymptotical converging condition of tracking error can be weakened to w(t)→0. Furthermore, a new adaptive fuzzy control scheme is proposed, which not only can make the closed-loop system always asymptotically stable, but also can make the parameter vector 0 converge to the optimum value under certain conditions. Simulation results for an unstable nonlinear system and a chaotic plant have demonstrated that the new adaptive fuzzy control scheme performes much superior to Wang's scheme.