Abstract: OBJECTIVE To investigate the effect of Tanreqing injection and montelukast sodium tablets on symptoms and blood gas index and pulmonary function of children with mycoplasma pneumonia. METHODS Children with mycoplasma pneumonia admitted to hospital from March 2017 to February 2019 were enrolled, and randomly divided into two groups, observation group(n=46) and control group(n=47). Both groups were given routine azithromycin treatment, based on this, observation group received the Tanreqing injection and montelukast sodium tablets, control group received the montelukast sodium tablets. The remission time of clinical symptoms, clinical efficacy, incidence of adverse reactions, lung function index, blood gas indexes including arterial partial pressure of oxygen(PaO₂), arterial partial pressure of carbon dioxide(PaCO₂) and arterial oxygen saturation(SaO₂), pulmonary function at admission and 2 weeks after treatment were observed. RESULTS The total clinical response rate of the observation group was significantly higher than that of the control95.65% vs 65.96%, P<0.05. The remission time of symptoms such as cough, fever, wheezing and moist rale in the observation group were shorter than those in the control group(P<0.05). After 1, 2 weeks of treatment in the observation group, PaO₂ levels were significantly higher than that in the control group(P<0.05), PaCO₂ levels were significantly lower than that in the control group(P<0.05); after 1 week of treatment in the observation group, SaO₂ levels were significantly higher than that in the control group(P<0.05). The incidence of total adverse reactions in the observation group was significantly lower than that in the control group8.70% vs 34.04%. At post-treatment 2 week, levels of FVC, FEV and MPEF in the two groups were increased in both groups, and were higher in the observation group than in the control group(P<0.05). CONCLUSION Application of Tanreqing injection and montelukast sodium tablets based on routine treatment can effectively shorten the remission time of clinical symptoms, restore the blood gas index level and reduce adverse reactions in children with mycoplasma pneumonia.