A medical electric drill is disclosed. The medical electric drill includes a drill and a microprocessor. The microprocessor is signal connected to the drill and calculates a displacement of the drill. The microprocessor includes a pressure sensor, a torque sensor and gravity sensor. The pressure sensor detects the pressure changes and applies a pressure signal to the microprocessor. The torque sensor detects the torque changes and applies a torque signal to the microprocessor. The gravity sensor detects the acceleration variation and applies an acceleration signal to the microprocessor. The microprocessor determines a work period according to the pressure signal and the torque signal. Besides, the microprocessor calculates the displacement of the drill by the acceleration signal during the work period.
