Provided are a motor rotation angle measurement device and method. The device may comprise: a signal conditioning circuit, configured to receive a three-phase output voltage of a motor and separately generate three square-wave signals; and a processor, configured to generate a six-multiplying frequency pulse whenever jumping of any one of the three square-wave signals, is detected in a rotation period of a motor, generate compensation pulses between the current six-multiplying frequency pulse and a next six-multiplying frequency pulse based on a time interval between the current six-multiplying frequency pulse and a previous six-multiplying frequency pulse and a preset compensation subdivision coefficient k, and accumulate the number of the compensation pulses, wherein the number of the compensation pulses is related to the rotation angle of the motor.