Objective: To investigate the analgesic effect of lidocaine ultrasonic spray in post-tonsillectomy patients. Methods: 65 post-tonsillectomy patients were randomly divided into two groups, the study group (33 cases) and the control group (32 cases). They were gave 0.5% lidocaine and 0.9% NS in ultrasonic spray respectively. Results: The study group was less painful than the control group, and had earlier oral feeding time and prolonged sleeping time (P<0.01). Conclusion: Lidocaine ultrasonic spray in post-tonsillectomy is safe, effective and harmless.