In view of the output characteristics of photovoltaic power generation system, it was vulnerable to the influence of external variables and presents asymmetric strong nonlinearity, and the output power often deviates from the maximum output power point. Here we discuss the advantages and disadvantages of several commonly used maximum power point tracking control method, the PUcurve was analyzed, and puts forward the method of asymmetric fuzzy and variable step incremental conductance method combining the variable step incremental conductance method here can be far away from the maximum power point on both sides, fast approaching the maximum power point. When further near the maximum power point near the interval, at this time, the asymmetric fuzzy control optimization, could effectively eliminate the oscillation phenomenon in the vicinity of the maximum power point, improve the stability of the system. The simulation results in MATLAB/Simulink showed that the proposed method had better dynamic performance.