Abstract:In order to study the course of postoperative pain and pain relief in infants,a perspective study with a cluster randomized controlled trials were Performed on 100 infants whohad undergone surgery.The method of assessment and measurement of Pain specially for theinfants was suggested by the author.It combined face scales and behavioral responses of illinfants.The results demonstrated that this method is convenient,accurate and practical. Infants indeed experienced a heavy and constant Pain course after operation.The postoperativepain will affect the treatment,recovery and even the prognosis of ill infants.So it is very important to Pay more attention to the diagnosis and treatment of infants'postoperative aain.The study suggests that the infant's postoperative Pain should be preventsd by administratingthe infants with medicine periodically.