OBJECTIVE To investigate the effect of adjuvant therapy with Maxing Shigan Decoction on inflammatory factors and pulmonary function in patients with chronic pneumonia. METHODS From May 2020 to February 2022, 160 patients with chronic pneumonia in our hospital were selected and divided into control group (n=80) and observation group (n=80) according to the random number table. The control group was given routine symptomatic treatment such as antibiotics On this basis, the observation group was given Maxing Shigan decoction as adjuvant therapy, and the pulmonary function [FEV1, FVC, FEV1/FVC], inflammation-related indicators [CRP, IL-6, TNF-α], condition [CPIS, SGRQ] , therapeutic efficacy, adverse reactions. RESULTS After treatment, FVC, FEV1, FEV1/FVC in the control group and observation group were significantly higher than those before treatment (all P<0.05), and the scores of CRP, IL-6, TNF-α, CPIS and SGRQ were significantly lower than those before treatment (all P<0.05); After treatment, the FVC, FEV1, FEV1/FVC of the observation group were significantly increased compared with those of the control group (all P<0.05), and the scores of CRP, IL-6, TNF-α, CPIS, and SGRQ were significantly decreased, and the differences were statistically significant. The treatment effective rates of the observation group and the control group were 96.25% and 85.00%, respectively, and the difference was statistically significant (P<0.05). There was no significant difference in the incidence of adverse reactions in patients with chronic pneumonia between the two groups (P>0.05). CONCLUSIONS Maxing Shigan Decoction assisted by conventional western medicine symptomatic treatment can effectively improve the pulmonary function and inflammatory response of patients with chronic pneumonia, which is beneficial to improve the patient"s condition and improve the therapeutic effect, and has good safety, which is worthy of clinical promotion.