Abstract：Objective：To observe the clinical effect of modified Renshen Sini Decoction combined with oxygen treatment for senile patients with chronic obstructive pulmonary disease and its effect on cognitive function. Methods：A total of 84 cases of senile patients with chronic obstructive pulmonary disease were divided into the control group and the observation group according to the random number table method， with 42 case in each group. The control group was given routine medicines and oxygen treatment，and the observation group was additionally treated with modified Renshen Sini Decoction based on the treatment of the control group. Traditional Chinese medicine(TCM) syndrome scores，Mini- Mental State Examination (MMSE) and Montreal Cognitive Assessment(MoCA) before and after treatment as well as the clinical effects in the two groups were compared. The levels of serum cortisol(COR)，adrenocorticotropic hormone (ACTH)，partial pressure of oxygen in arterial blood(PaO2)，partial pressure of carbon dioxide in arterial blood (PaCO2) and lung function indexes before and after treatment in the two groups were compared. Results： After treatment，the total effective rate in the observation group was higher than that in the control group (P＜0.05). After treatment， the scores of MMSE and MoCA in the two groups were increased when compared with those before treatment(P＜0.05)， and the scores of primary， secondary and total symptoms were decreased(P＜0.05)； the levels of forced vital capacity(FVC)，peak expiratory flow(PEF)， forced expiratory volume in the first second(FEV1)，COR and PaO2 in the two groups were increased when compared with those before treatment(P＜0.05)，and the levels of ACTH and PaCO2 were decreased(P＜ 0.05)；the improvement of the above indexes in the observation group was better than that in the control group(P＜0.05). Conclusion： The therapy of modified Renshen Sini Decoction combined with oxygen treatment for senile patients with chronic obstructive pulmonary disease has a definite curative effect， which can effectively improve lung function and blood gas indexes，regulate the levels of COR and ACTH， and enhance cognitive function.