Objective To study the effect of ultrasonic cleaner( UC) on electrocardiogram( ECG) in anesthetized rats． Method The electrocardiogram was observed by RM6240 Multi-channel physiological signal acquisition decency via standard limb lead II in anesthetized rats when the ultrasonic cleaner was working for different time． Result When ultrasonic cleaner worked for 2 min，15min and 30min，heart rate( HR) of rats increased significantly and QRS complex interval in electrocardiogram was significantly shortened at the same time． But heart rate and QRS complex interval recovered after the UC stopped． Conclusion Ultrasonic cleaner at work produced recoverable adverse effect on electrocardiogram in rats． Therefore，ultrasonic cleaner should be placed as far as possible away from the rat breeding room．