The variable pitch system is an important part of the wind turbine, which adjusts the constant power by changing the pitch angle, and plays a key role in the safe operation of the system.Aimed at the parameter uncertainty and external disturbance in the hydraulic variable pitch system, an H∞ robust control strategy for the wind turbine variable pitch system was proposed.The mathematical model of the hydraulic variable pitch system was simplified, which was changed into the state equation of the nominal object.According to the performance requirements of the system, the weighted function which met the system requirements in the process of the mixed sensitivity optimization was selected, and then the state space realization of the system generalized controlled object was obtained. The H∞ controller was obtained by solving the Riccati equation. The effectiveness and superiority of the control strategy were verified by simulation and comparison with the traditional PI variable pitch control strategy