Objective To study the effect improvation of lung function and prognosis of singulair and seretide for moderate to severe AECOPD . Methods 78 patients associated with moderate to severe AECOPD from January 2014 to June 2016 in our hospital were researched.They were divided randomly into observation and control groups according to the order of admission, 39 cases in each group.In the control group, they were treated by conventional anti-infective, expectorant, oxygen, suction seretide.In the observation group, using singulair on the basis of the control group.Clinical data, clinical efficacy, clinical symptoms begin to improve time, hospitalization time, blood gas analysis (PaO2, PaCO2) after five days and pulmonary function after treatment forced expiratory volume in one second ( FEV1 ) , call gas peak velocity ( PEF) , forced expiratory volume in one second than the forced vital capacity (FEV1/FVC), maximum mid-expiratory flow rate (MMEF) were compared with each other.Results Their clinical data of patients and other general information and basic condition had no significant difference between each other.The effective rate of observation group and control group were 97.44%and 87.18%, clinical effecicy of observation group was better than the control group, the difference was statistically significant (u=2.2805, P<0.05).Postoperative hospital stay, time of symptoms began to improve of the observation group were shorter than the control group, the difference was statistically significant (P<0.05), PaO2 of 5-day post-treatment of observation group was higher, and PaCO2 was lower, the difference was statistically significant (P<0.05).Lung function of two groups of patients had no significant difference before treatment, after treatment, pulmonary function in the observation group (including FEV1, PEF, FEV1/FVC, MMEF) was better than the control group, the difference was statistically significant (P<0.05).Conclusion Seretide combined with singulair to treat severe AECOPD has a good effect, it can significantly improve the therapeutic effect and improve the patient's lung function.