Objective：To observe lung distension No.2 prescription in treating syndrome differentiation factors in patients with syndrome of qi and yin deficiency of lung and kidney in chronic obstructive pulmonary disease(COPD)stationary phase and changes during this process.Methods：Divided 70 cases of patients with syndrome of qi and yin deficiency of lung and kidney in COPD stationary phase who met the inclusion criterion into two groups randomly，35 cases in each group.The treatment group was given lung distension No.2 prescription on the basis of routine western medicine treatment，while the control group was treated with placebo treatment based on routine western medicine treatment.The course of treatment for both groups lasted for 3 months.Compared the changes of syndrome differentiation factors of disease location and nature of disease in the two groups before and after treatment.Results：33 cases were completely analyzed in the two groups respectively.The scores of syndrome differentiation factors of disease locations such as lung and kidney and of natures of disease such as qi deficiency， yin deficiency， yang deficiency and phlegm in the treatment group were significantly decreased，compared the results before and after treatment，differences being significant(P＜0.01).After treatment，there were significant differences being found in the comparisons of the scores of the syndrome differentiation factors of disease location and nature of disease in the two groups(P＜0.01).After treatment，there were significant differences being found in the comparisons of the pathological grades of disease location in the kidney in the two groups(P＜0.05).After treatment，compared the pathological grades of syndrome differentiation factors of natures of disease such as qi deficiency，yin deficiency and phlegm in the two groups，there were significant differences being found(P＜0.05，P＜0.01).Conclusion：The application of lung distension No.2 prescription can reduce the scores of syndrome differentiation factors of disease location and nature of disease in patients with syndrome of qi and yin deficiency of lung and kidney in COPD stationary phase and improve the Chinese medicine pathological damage to a certain extent.