〔Abstract〕 Objective To analyze the clinical effect of multi-functional frequency conversion therapy instrument in the auxiliary treatment of bronchial pneumonia in children. Methods A total of 340 children with bronchial pneumonia admitted to Huiyang Sanhe Hospital from January 2017 to October 2019 were selected as the research objects. They were randomly divided into a control group of 160 cases and an observation group of 180 cases. The control group received conventional drugs for treatment, and the observation group were combined with a multi-function frequency conversion therapy device on the basis of conventional drug treatment. The efficacy, time of clinical symptom resolution, hospitalization rate, and treatment cost of the two groups of children were evaluate and compared. Results The total effective rate of the observation group was 93.33%, significantly higher than 81.25% of the control group, the difference was statistically significant (P < 0.05); The observation group had a shorter time for clinical symptoms such as cough, shortness of breath and phlegm to subside compared with the control group, the difference was statistically significant (P < 0.05); The hospitalization rate of children in the observation group was 10.00%, lower than 22.50% of the control group, and the difference was statistically significant (P < 0.05); The treatment cost of children in the observation group was less than that in the control group, the difference was statistically significant (P < 0.05). Conclusion The adjuvant treatment for children with bronchial pneumonia with a multi-functional frequency conversion therapeutic device has a definite effect, which can effectively improve the symptoms of the children, shorten the treatment time, save the treatment cost, and reduce the hospitalization rate of the children.