Objective To explore whether theophylline has clinic effects of treatment on bronchiolitis in children. Methods 128 children with bronchiolitis in our hospital were divided into the experiment and the control at random, in the meantime, grouped into the severe and the mild according to their condition. The children in the control were used traditional methods. The children in the control were taken theophylline, as well as used traditional methods. All patients in our hospital were checked up pulmonary function, alkyladenine glycosylase in trachea secretion, serum interleukin 8, cytotaxonomy in trachea secretion on time, after the third day and the 7th day. Results The pulmonary function and cytotaxonomy of the patients in the experiment were more improvement than that of the control. Their alkyladeniue gtycosylase in trachea secretion and serum interleukin 8 were very lower than that of the control. The cure rate in the mild and the severe of the experi-ment were higher than that of the control. Conclusion Administrating theophyUine by oral can improve the pulmonary function, relax a block of the small trachea, and raise the cure rate of patients with bronchiolitis.