In the electric vehicle, the traction motor drive system can be improved by using the sensorless control method. Its volume and cost can be decreased, and reliability can be increased because of removed position sensor. However, the polarity of estimated rotor is sometimes reversed by the external torque or noise. In that case, the output torque is generated in the opposite direction, thereby deteriorating driving safety. In this paper, a method for automatic recovering of polarity reversal is proposed during traction motor sensorless control. The effectiveness of proposed method is verified through hardware-in-the-loop tests.