The measurement of partial discharge (PD) under high frequency impulse voltage may be effective to check the insulation condition of the motor insulation system. Depending on the sensor, there were two methods of detecting PD under high frequency voltage for the motor insulation system: Highfrequency Current Transducer and ultrahigh frequency antenna. The PD activities mainly occur in both pulse rising edge and falling edge under the impulse voltage. The amplitudes of PD in both rising edge and falling edge were higher under the same applied voltage. In the qualification test of stator insulation system of wind turbines, the PD inception voltages of the coil were decreasing with the aging test. the impulse voltage insulation class and type of stator insulation system are determined by the qualification test.