Abstract： Objective： To observe the clinical effect of modified Tongfu Xuanfei Decoction on mycoplasma pneumoniae pneumonia with syndrome of phlegm- heat obstructing the lung in children. Methods：A total of 80 children with mycoplasma pneumoniae pneumonia with syndrome of phlegm-heat obstructing the lung were selected as the study subjects，and divided into the observation group and the control group according to the random number table method，with 40 cases in each group. The two groups were given routine symptomatic treatment； the control group was additionally treated with Azithromycin based on routine treatment， and the observation group was additionally treated with modified Tongfu Xuanfei Decoction based on the treatment of the control group. The two groups were treated for 7 days. The clinical effects in both groups were evaluated； the improvement time of symptoms， traditional Chinese medicine (TCM) syndrome scores，and levels of serum procalcitonin (PCT)，C-reactive protein (CRP) and interleukin-6 (IL-6) were compared before and after treatment between the two groups；the incidence of adverse reactions was also observed. Results： The total effective rate was 92.50% in the observation group， higher than that of 75.00% in the control group (P＜0.05). The disappearance time of cough and pulmonary rales was respectively shorter than that in the control group (P＜0.05). After treatment， the scores of primary and secondary symptoms and total scores of TCM syndromes in the two groups were decreased when compared with those before treatment (P＜0.05)，and the above scores in the observation group were lower than those in the control group (P＜0.05). After treatment，the levels of serum PCT，CRP and IL- 6 in the two groups were decreased when compared with those before treatment (P＜0.05)，and the levels in the observation group were lower than those in the control group (P＜0.05). There was no serious adverse reaction during treatment in the two groups. Conclusion： Modified Tongfu Xuanfei Decoction has a significant clinical effect on mycoplasma pneumoniae pneumonia with syndrome of phlegm-heat obstructing the lung in children，which can effectively mitigate the symptoms，and decrease the levels of serum inflammatory factors with good safety.