Objective:To observe the clinical efficacy of Xu’s Danmajia Formula in treating chronic obstructive pulmonary disease (COPD) with syndrome of turbid phlegm obstructing lung. Methods106 COPD patients with syndrome of turbid phlegm obstructing lung were randomly divided into the treatment group and control group, 53 cases in each group. The treatment group was treated with Xu’s Danmajia Formula, while the control group was treated with Guilong Kechuanning Capsule, with a course of 10 days. The clinical efficacy and safety and the acute exacerbation within 3 months of follow-up were observed. The changes on TCM syndrome score, CAT score, percentage of forced expiratory volume in the first second to the predicted value (FEV,1,%), and percentage of forced expiratory volume in the first second to the forced vital capacity (FEV,1,/FVC) were compared.  Results:①Finally 96 patients completed the trial, among 50 cases in the treatment group and 46 cases in the control group. ②The total effective rates were 98.0% in the treatment group and 63.0% in the control group, the clinical efficacy of the treatment group was significantly better than that of the control group (P,<,0.05). ③Compared with treatment before, the level of FEV,1,% in the treatment group showed an increasing tendency after treatment, but with no statistically significant difference (P,>,0.05). And in the treatment group, there was no statistically significant difference on FEV,1,/FVC level between treatment before and after (P,>,0.05). In the control group, there were no statistically significant differences on the levels of FEV,1,% and FEV,1,/FVC between treatment before and after (P,>,0.05). After treatment, there were no statistically significant differences on the levels of FEV,1,% and FEV,1,/FVC between the two groups (P,>,0.05). ④No drug-related adverse reactions were observed in both groups during the trial, and no abnormality in routine safety examination was observed before and after treatment. During the follow-up, no acute exacerbation of chronic obstructive pulmonary disease occurred in the treatment group, and 2 patients in the control group showed asthma exacerbation and were alleviated after treatment with bronchodilators and hormones.  Conclusion:Xu’s Danmajia Formula in treating chronic obstructive pulmonary disease with syndrome of turbid phlegm obstructing lung shows satisfactory clinical efficacy, which can significantly relieve the clinical symptoms and improve the quality of life of patients.