Objective To analyze chest CT manifestations of 46 children with mycoplasma pneumonia, and to improve the diagnostic level of mycoplasma pneumonia in children by chest CT. Methods CT data of 46 cases with mycoplasma pneumonia in our department from 2011 June to 2011 December were retrospectively compared and analyzed. Results 34 cases(73.9%) showed unilateral lung lesions, of which 20 cases showed in the right side(58.8%), 14 cases showed in the left (41.2%). 12 cases(26.1%) showed bilateral lesions. 20 cases(43.5%) showed single lobe and segment lesion; 26 cases(56.5%) showed multiple lobe and segment lesions. Lesions of 14 cases distributed in the right upper lobe, 6 cases in the middle lobe and 21 cases in inferior lobe; lesions of 16 cases distributed in the left upper lobe, 6 cases in the middle lobe and 18 cases in inferior lobe. Among them, the lung segment infiltration(large opacities) were showed in 32 cases; lobular parenchyma infiltration(punctate or patchy opacities) were showed in 30 cases; the lung stroma infiltration(scattered spots or patchy shadow) were showed in 10 cases; ground glass opacity were showed in 4 cases. Large opacities and patchy opacities were existed in multiple lobe lesions together. In addition, there were other lesions including hilar lymph node enlargement in 3 cases, pleural effusion in 11 cases and pulmonary atelectasis in 2 cases. Pulmonary interstitial infiltration were absorbed in 10 cases after 7 days' systematic treatment. Pulmonary parenchyma infiltration were absorbed in 7 days in 11 cases, 14 days in 13 cases, 21 days in 7 cases and more than 21 days in 5 cases combined with the other organ involvement. Conclusion Mycoplasma pneumonia showed certain features in chest CT images. More lesions located in unilateral lung than bilateral lungs, and more lesions located in the right lung than the left lung. Large opacities are the most common feature, then the punctate or patchy opacities. The spot or patchy shadows are uncommon. These characteristics can help the early diagnosis, treatment and evaluation of the efficacy.