Abstract: A set of AC servo motor control system was developed for eddy current inspection in this paper, which was used for heat exchanger of conventional island in nuclear power plant. The pusher was controlled by human-machine interface, which was easy to operate. With the application of AC servo motor, the power met the practical requirement, and the motor had no interference on the signals. According to the programming, the speed of pusher and take up reel had a good matching, therefore the system could pull probe automatically at constant speed. The on-site use showed that the amplitude of the auto collected signal was stable and had good signal to noise ratio, and the location for defect was accurate. The system was helpful to improve the quality of the collected signals.