Abstract: The study was aimed to overcome the problem of heat dissipation of the MW-class wind turbine convertor. In this study the heat sink plate with Vertical water cooling was designed to create a simplified model of the heat sink,the heat transfer mode of the main heat source Insulated Gate Bipolar Transistor（IGBT）in the converter was analyzed by using the finite element method. Simulation results show that when the initial temperature of the heat source set to 86.85 ℃,the circulation pump operates at low power consumption,and the inlet flow rate of the fluid becomes between 1 m/s and 2 m/s. The maximum static temperature of the heat source is 34.65 ℃ and the overall temperature drops by 52.20 ℃.