Abstract：Objective：To observe the clinical effect of the therapy of Shenmai injection combined with trimetazidine on elderly patients with chronic pulmonary heart disease complicated with respiratory failure. Methods：A total of 78 elderly patients with chronic pulmonary heart disease complicated with respiratory failure were selected and divided into the control group and the observation group according to the random number table method， with 39 cases in each group. The control group was additionally treated with trimetazidine based on the routine treatment， and the observation group was additionally treated with Shenmai injection based on the treatment of the control group. After 14 days of continuous treatment，the clinical effects， the lung function indexes， including the percentage of forced expiratory volume in one second(FEV1) to the predicted value(FEV1% )， ratios of FEV1 and forced vital capacity(FVC) (FEV1/FVC) and peak expiratory flow(PEF)， arterial blood gas indexes， including partial pressure of oxygen(PaO2)， partial pressure of carbon dioxide(PaCO2) and potentail of hydrogen(pH)，serum N- terminal pro- brain natriuretic peptide(NT- proBNP)， D- dimer(D- D)， endothelin- 1(ET- 1)， heart rates， respiratory rates and adverse reactions were observed and compared between the two groups. Results： The total effective rate was 100% in the observation group and 89. 74% in the control group，the difference being significant(P＜0.05). Before treatment，there was no significant difference being found in the comparisons of levels of FEV1%， FEV1/FVC and PEF between the two groups(P＞0.05)；after treatment，the levels of FEV1%，FEV1/FVC and PEF in the two groups were increased when compared with those before treatment(P＜0.05)， and the above three levels in the observation group were higher than those in the control group(P＜0.05). Before treatment，the levels of PaO2，PaCO2 and pH were compared between the two groups，there being no significant differences(P＜0.05). After treatment， the levels of PaO2 and pH in the two groups were increased when compared with those before treatment，and the level of PaCO2 were decreased(P＜0.05)； the levels of PaO2 and pH in the observation group were higher than those in the control group，and the level of PaCO2 in the observation group was lower(P＜0.05). Before treatment， there was no significant difference in the comparison of the levels of NT-proBNP，D-D，and ET- 1 between the two groups(P＞ 0.05)； after treatment， the levels of NT- proBNP， D- D， and ET- 1 in the two groups were decreased when compared with those before treatment(P＜0.05)，and the above three levels in the observation group were lower than those in the control group(P＜0.05). Before treatment，there was no significant difference in the comparison of heart rates and respiratory rates(P＞0.05)； after treatment， the heart rates and respiratory rates in the two groups were decreased when compared with those before treatment(P＜0.05)， and the above two rates in the observation group were lower than those in the control group(P＜0.05). The incidence of adverse reactions was 12.82% in the observation group，and was 7.69% in the control group， there being no significance in the difference(P＞0.05). Conclusion： Based on the routine treatment， the therapy of Shenmai injection combined with trimetazidine for elderly patients with chronic pulmonary heart disease complicated with respiratory failure， can improve the heart and lung function and the levels of arterial blood gas indexes in the short term， reduce the heart rate and respiratory rate， and reduce the levels of heart failure markers，and by doing so，the clinical effects can be improved.