Abstract: Objective: To explore the clinical characteristics of children's Mycoplasma pneumonia(MP) in different age groups and to improve the recognition of the disease.Methods: Ninety-four cases of MP were divided into three groups:infants,preschool children and school children,and their clinical data were analyzed retrospectively.Results: Fourty-three cases(45.75%) of the cases were school children.The infants group was significantly different from the preschool children group and the school children group in symptoms,physical signs,sternum and specific anti-MP-IgM antibody titer(P<0.05).However,the preschool children group and the school children group were similar in those aspects(P>0.05).The extra-pulmonary complications occurred in 18 cases,with no significant difference in the incidence rates among the three groups(P>0.05).All the cases responded well to erythromycin and azithromycin.Conclusions: Children's MP occurs most frequently in school children.The clinical characteristics of different groups are relevant to the development level of immunity and immunoreaction.Macrolides antibiotics is effective for treatment of MP.