Abstract：Objective：To observe the clinical effect of modified Buyang Huanwu Decoction combined with extended burr hole drainage of skull on chronic subdural hematoma. Methods：A total of 83 patients with chronic subdural hematoma caused by external injury were randomly divided into the observation group and the control group，with 42 and 41 cases in each group. The two groups were given extended burr hole drainage of skull， and the observation group was additionally treated with Buyang Huanwu Decoction for 90 days. Before treatment and after treatment for 10 days，30 days and 90 days，the scores of Chinese Stroke Scale (CSS) for neurological severity，and Activity of Daily Living (ADL) were compared，respectively. After treatment for 10 days，30 days and 90 days，the postoperative percentage of residual hematoma and clinical effects in both groups were also compared， respectively. Results： After treatment for 10 days， there was no significant difference being found in the comparison of percentage of residual hematoma between the two groups (P＞0.05)；after treatment for 30 days and 90 days，the percentages of residual hematoma in the two groups were decreased (P＜0.05)，and the percentage of residual hematoma in the observation group was lower than that in the control group (P＜0.05). Before treatment， there was no significant difference being found in the comparisons of scores of CSS and ADL between the two groups (P＞ 0.05)；after treatment for 10 days，30 days and 90 days，the CSS scores in both groups were gradually decreased (P＜0.05)，and the ADL scores were gradually increased (P＜0.05)，and the CSS scores at the same time points in the observation group were lower than those in the control group (P＜0.05)，and the ADL scores were higher than those in the control group (P＜0.05). The total effective rate of observation group was 95.24% ， higher than that of 70.73% in the control group (P＜0.05). Conclusion： Modified Buyang Huanwu Decoction combined with extended burr hole drainage of skull for chronic subdural hematoma can free the collateral vessels，invigorate blood，and tonify qi to mitigate the disease，reduce the residual hematoma of patients，alleviate the clinical symptoms and enhance the clinical effect.