The aim of this study was to evaluate whether high-frequency chest wall oscillation (HFCWO) could improve the symptoms of children with Mycoplasma pneumoniae pneumonia.We recruited 157 children with M. pneumoniae pneumonia between February 2017 and December 2018. We collated clinical data for each subject and then randomly divided the subjects into a control group (n=82) and an HFCWO group (n=75). Subjects in the control group were given azithromycin, budesonide, ipratropium bromide, and salbutamol. The HFCWO group received all of the treatments given to the control group but also received HFCWO. A range of tests were carried out on each group before treatment and 7 days after treatment, including chest X-ray, routine blood tests, C-reactive protein (CRP) levels, and lung function; we also recorded the duration of fever and cough. Treatment efficacy (based on upper respiratory tract symptoms) was better in the HFCWO group than in the control group (P=0.03). Levels of CRP were significantly lower in the HFCWO group. Patients in the HFCWO group also had shorter durations of fever and cough, and shorter stays in hospital (P<0.05). Treatment costs were also significantly lower in the HFCWO group(P<0.05).Relative to predicted values, forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF), were all significantly improved in the HFCWO group(P<0.05). In conclusion, the combination of adjuvant treatment with HFCWO will be of significant benefit to children with M. pneumoniae pneumonia. This treatment combination improves clinical symptoms, reduces the length of hospital stay, and reduces costs.