Abstract: OBJECTIVE To explore the clinical effect of Mahuang Shengma Dayuan Tang combined with tigecycline (TGC) on treatment of pan-drug resistant Acinetobacter baumannii (PDRAB) pneumonia and observe the impact on serum inflammatory factors. METHODS A total of 84 patients with PDRAB pneumonia who were treated in Wuhan Traditional Chinese Medicine Hospital from Apr. 1, 2022 to Apr. 1, 2024 were enrolled in the study and were randomly divided into the combination group (treatment with Mahuang Shengma Dayuan Tang combined with TGC) and the TGC group (treatment with only TGC), with 42 cases in each group. The clinical therapeutic effect, bacterial eradication rates, levels of inflammatory factors, immune function indexes and incidence of adverse reactions during treatment period were observed and compared between the two groups of patients. RESULTS The total effective rate of clinical treatment of the combination group was 92.86% (39/42), higher than 71.43% (30/42) of the TGC group(P＜0.05). The total clearance rate of the combination group was 83.33% (35/42), higher than 61.90% (26/42) of the TGC group (P＜0.05). The CRP, neutrophil ratio (N%), serum procalcitonin (PCT), interleukin-6 (IL-6) and WBC of the two groups were lower after the treatment than before the treatment, and the above indicators of the combination group were even lower(P＜0.05). The levels of IgG, IgM and IgA of the two groups were higher after the treatment than before the treatment, and the levels of the above indicators of the combination group were even higher (P＜0.05). There was no significant difference in the total incidence of adverse reactions between the two groups (χ²=0.553,P=0.457). CONCLUSION Mahuang Shengma Dayuan Tang combined with TGC can remarkably improve the clinical therapeutic effect on PDRAB pneumonia and effectively reduce the levels of inflammatory factors.