Abstract: An electro-hydraulic servo synchronizer for MW wind turbine generator system includes a 2K-H differential planetary drive mechanism and a direct drive volume control system. The 2K-H differential planetary drive mechanism comprises a planet carrier, a planet gear, a ring gear, a sun gear, and a control gear, the input end of the planet carrier is an input shaft I, the output end of the sun gear is an output shaft II, the central shaft of the control gear is a shaft III. The direct drive volume control system comprises a constant displacement motor, a two-way constant delivery pump and a servo motor, the servo motor is connected with the two-way constant delivery pump, the two-way constant delivery pump is connected with the constant displacement motor, and the constant displacement motor is connected with the shaft III, so as to drive the control gear.