For the classical maximum power point tracking algorithm, the setting of small step increases the speed of maximum power tracking of photovoltaic power generation system and the stability of operation in stable state. To solve this problem, this paper designs a maximum power point tracking system based on booster circuit, and adopts fuzzy auto-disturbance rejection control to improve the conductance increment method with variable step length. Based on the relationship between the rate of conductance change and the maximum power point conductance, the step size of the adrc is adjusted by using the fuzzy logic control. The MPPT system of photovoltaic power generation is designed by combining the incremental conductance method and the improved fuzzy control method with the correction factor. The control method does not depend on the mathematical model of the system, the design is flexible, the control effect is robust, stable and accurate. It can be used for reference for other types of solar photovoltaic power generation control system.