Abstract： Objective： To observe the clinical effect of modified Taohong Siwu Decoction combined with hyperbaric oxygen for diabetic lower extremity vascular disease. Methods： A total of 60 cases of patients with diabetic lower extremity vascular disease were selected and divided into the observation group and the control group according to the random number table method， with 30 cases in each group. The control group was treated with hyperbaric oxygen，and the observation group was additionally treated with modified Taohong Siwu Decoction based on the treatment of the control group. The clinical effects and the changes in scores of symptoms and signs，vascular internal diameter and blood flow of popliteal artery and dorsalis pedis artery，and vascular endothelial function including nitric oxide (NO) and endothelin- 1 (ET-1) were compared between the two groups. Results：The total effective rate was 93.33% in the observation group，higher than that of 73.33% in the control group，the difference being significant between the two groups (P＜0.05). Before treatment，there was no significant difference being found in the comparison of scores of symptoms and signs between the two groups (P＞0.05)； after treatment， the scores of symptoms and signs in the two groups were decreased when compared with those before treatment (P＜ 0.05)，and the scores of symptoms and signs in the observation group were lower than those in the control group (P＜0.05). Before treatment，there was no significant difference being found in the comparison of the vascular internal diameter of popliteal artery (left and right) and dorsalis pedis artery (left and right) between the two groups (P＞0.05)； after treatment， the above indexes in the two groups were increased when compared with those before treatment (P＜0.05)， and the above indexes in the observation group were higher than those in the control group (P＜0.05). Before treatment， there was no significant difference being found in the comparison of the blood flow of popliteal artery (left and right) and dorsalis pedis artery (left and right) between the two groups (P＞0.05)；after treatment，the above indexes in the two groups were increased when compared with those before treatment (P＜0.05)， and the above indexes in the observation group were higher than those in the control group (P＜0.05). Before treatment，there was no significant difference being found in the comparison of the levels of NO and ET-1 in serum between the two groups (P＞0.05). After treatment， the levels of NO in serum in the two groups were increased when compared with those before treatment (P＜0.05)，and the levels of ET-1 were decreased when compared with those before treatment (P＜0.05)；the improvement of the above two indexes in the observation group was more significant than that in the control group (P＜0.05). Conclusion： Modified Taohong Siwu Decoction combined with hyperbaric oxygen for diabetic lower extremity vascular disease has a definite curative effect， and can effectively relieve symptoms and signs of patients， increase vascular internal diameter and blood flow，and improve vascular endothelial function.