【Abstract】Objective To investigate the clinical efficacy of azithromycin in the treatment of children with asthmatic attack and mycoplasma pneumonia infection and lung function improvement.Methods From January 2012 to January 2014,62 cases of asthma combined with mycoplasma pneumonia infection were randomly divided into observation group and control group ，31 cases in each. Two groups were given conventional treatment of asthma,and the observation group received azithromycin treatment based on conventional treatment,control group with erythromyc treatment.The remission and disappearance time of clinical symptoms，clinical efficacy, the changes of lung function, the number of WBC in peripheral blood and the incidence of adverse reactions were compared after 4 courses of treatment in the children of two groups.Results The time of shortness of breath remission and the disappearance time of cough and wheezing in the observation were lower than those in the control group, and the differences were statistically significant (P<0.05).Of 31 cases in the observation group，10 cases were clinically controlled, 12 cases effective, 7 cases improved, 2 cases ineffective.The total efficiency of the treatment were 93.5%(29cases), higher than that of the control group of 71%(22 cases), and the difference was statistically significant (P<0.05).Pulmonary function of children in the observation group improved significantly than that of the control group, and the difference was statistically significant (P<0.05).Peripheral white blood cell counts of the observation group after treatment were lower than those before treatment,and the difference was statistically significant (P<0.05).After treatment the number of peripheral white blood cells in the observation group were lower than those in the control group,and the differences were significant (P<0.05).Gastrointestinal reaction occurred in 3 cases of 31 patients in the observation group and rash, ALT increased and local pain in