Objective To investigate the roles of interleukin(IL)-25,eosinophils in the occurrence of bronchial asthma.Methods Selected 30 cases of acute episode of asthma(asthma group),and ease a group of 23 cases of asthma treatment(remission group),20 cases of the normal control group.Using the method of gradient ultrasonic atomizing inhalation of Hyperosmotic saline collection of induced sputum specimens,by ELISA method for the determination IL-25 level in induced sputum,count of eosinophils,analysis of correlation between them.Results Group IL-25 in induced sputum of asthma and eosinophil levels[(313.12±75.64)ng/L vs(236.43±57.90)ng/L]were sig-nificandy higher than the control group[(0.386±0.267) × 109/L vs(0.005±0.002) × 109/L],and significantly higher than acute stage in remission stage[(268.63 + 40.19) ng/L,(0.120 + 0.016) × 109/L](P ＜ 0.05).Conclusion IL-25 has an important role in asthma development.It provides a new way of thinking for monitoring and treatment.