The output characteristics of photovoltaic cell system become asymmetric along with strong nonlinear, and the output power of system always deviates from the maximum power point(MPP) as the external environment change. By analyzing the mechanism and structure of perturb and observe (P O) method, the P O method was used to track the MPP of PV to improve the efficiency of photoelectric energy conversion. Aiming at the shortcomings of P O, the asymmetric fuzzy control strategy was proposed with employing different membership functions and fuzzy control rules at both sides of the MPP, the fuzzy controller was designed by the fuzzy toolbox of the matlab software. Based on the established Matlab/Simulink simulation model, the MPPT curves both of the P O method and the asymmetric fuzzy control method were compared and analyzed when the external environment changed. The simulation results showed that the proposed method improved the dynamic and steady state performance of MPPT and can more efficiently, quickly and accurately track the MPP in any the external environment.