Abstract: Objective: To explore the clinical manifestations and extrapulmonary complications of Mycoplasma pneumoniae (MP) in children. Methods: The clinical data of 438 cases of children MP were analyzed retrospectively. Results: Three hundred nineteen of all the MP cases were preschool-age children (3-6 years). Among the 153 cases of extrapulmonary complications, 143 cases were no less than 3 years of age and 10 cases were under 3 years. The complications occurred mostly in the circulative system, digestive system and nervous system (51.0%, 29.4% and 17.6%, respectively). All the cases improved after being treated with Azithromycin for 14 days. Assistanted examination showed that the blood MP-IgM in all the cases was ≥ 1:80 and MP culture positive rate was 32.6%. Carinii pneumonia changes was seen in 238 cases, alveolus inflammation in 121 cases and mixed pathological changes in 79 cases. Conclusions: Clinical and chest radiograph examination of MP infection absents speciality and is apt to extrapulmonary complications. If extrapulmonary complication is its first symptom, error diagnosis is commonly inevitable. If the pneumonia presents no ideal treatment changes and is accompanied by extrapulmonary complications, MP infection must be considered. In the same time, related examinations must be conducted to achieve early diagnosis and treatment.