Abstract： Objective： To observe the clinical effect of Shenmai injection combined with routine western medicine for acute exacerbation of chronic obstructive pulmonary disease(AECOPD) complicated with respiratory failure. Methods：A total of 80 cases of patients with AECOPD complicated with respiratory failure were divided into the observation group and the control group according to the random number table method， 40 cases in each group. The control group was treated with routine western medicine，and the observation group was additionally treated with Shenmai injection based on the treatment of the control group. The clinical effect in the two groups was evaluated after treatment. Results：After treatment，the total clinical effective rate was 87.50% in the observation group，higher than that of 67.50% in the control group，the difference being significant(P＜0.05). After treatment，the forced vital capacity(FVC) in the two groups were deceased when compared with those before treatment，and the forced expiratory volume in one second(FEV1) and the ratio of forced expiratory volume in one second to forced vital capacity(FEV1/FVC) were increased when compared with those before treatment；FEV1 and FEV1/ FVC in the observation group were higher than those in the control group，and FVC was lower than that in the control group； the comparison of each index of the lung function after treatment between the two groups showed significance in the difference(P＜0.05). After treatment， the levels of partial pressure of carbon dioxide(PaCO2) and partial pressure of oxygen (PaO2) in arteries in the two groups were increased when compared with those before treatment，and the levels of PaCO2 were decreased when compared with those before treatment； the levels of SaO2 and PaO2 in the observation group were higher than those in the control group，and the level of PaCO2 was lower than that in the control group；the comparison of each index of the blood gas after treatment between the two groups showed significance in the difference(P＜0.05). Before treatment，compared the levels of the indexes of immune function including CD3+，CD4+，CD8+ and CD4+/CD8+，there was no significance in the difference(P＞0.05)；after treatment，the levels of CD3+，CD4+ and CD4+/CD8+ in the two groups were increased when compared with those before treatment，and the levels of CD8+ were decreased when compared with those before treatment；the levels of CD3+，CD4+ and CD4+/CD8+ in the observation group were higher than those in the control group，and the level of CD8+ was lower than that in the control group；the comparison of each index of the immune function after treatment between the two groups showed significance in the difference(P＜0.05). Conclusion： In the treatment of acute exacerbation of chronic obstructive pulmonary disease(AECOPD) complicated with respiratory failure， the curative effect of the therapy of Shenmai injection combined with routine western medicine is more significant than that of the simple western medicine. It can improve the indexes of the lung function and blood gas function，and body immunity，which has important value in the clinical treatment of patients with AECOPD complicated with respiratory failure.