【Abstract】 Objective To investigate the clinical efficacy of pirfnidone in treatment of COPD complicated with pulmonary fibrosis and its effects on pulm pulmonary onary function, antifibrosis and inflammatory markers. Methods 96 COPD patients with pulmonary fibrosis treated in our hospital from September 2017 to October 2016 were selected. According to the random number table, 96 patients were divided into the control group and the observation group with 48 cases in each group. The patients in the control group were treated with routine treatment, while the observation group was treated with pirfidone. The clinical efficacy, pulmonary function, anti pulmonary fibrosis, inflammatory factors, quality of life and adverse reactions were compared between the two groups. Results The total clinical effective rate of the observation group was significantly higher than that of the control group (9583% vs 6041%)(P＜0.05). The levels of NOX4 and TGFβ1 in the two groups were significantly lower than those before the treatment. The decrease of NOX4 and TGFβ1 levels in the observation group was significantly greater than that in the control group (P＜0.05). After treatment, the HA and LN of two groups were decreased, and the level of HA and LN in the observation group was significantly lower than that of the control group (P＜0.05). The level of IL8, TNFα and IL18 in the observation group after treatment were significantly greater than those in the control group(P＜0.05). The level of FVC, FEV1 and FEV1/FVC in the observation group was significantly higher than that of the control group (P＜0.05). The respiratory symptoms, limited activities, the influence of the disease and the total score of SGRQ in the two groups were significantly changed after treatment. After treatment, the respiratory symptoms, restriction of activity, the influence of the disease and the total score of SGRQ in the observation group were significantly lower than that of the control group (P＜0.05). No serious adverse reactions were observed in the two groups during treatment. Conclusion Pifimidone is effective in the treatment of COPD with pulmonary fibrosis. It can effectively improve the pulmonary function, anti pulmonary fibrosis and inflammation.