Objective: To study the effect of Naomaitai capsule on cognitive dysfunction of vascular dementia patients. Method: Eighty four vascular dementia patients were randomly divided into therapeutic group and control group (n=41 each). The therapeutic group was treated by Naomaitai capsule (2 capsules, tid) and the control group by Naofukang (2 tablets, tid). The therapeutic course was 12 weeks. Before and after treatment, mimi-mental state examination (MMSE) grade and variation of frenquently appeared potential (P300) were evaluated. Clinical efficacy was evaluated for the two groups. Result: After the therapeutic course, the total efficacy of the observation group was better than that of the control group, the difference was statistically significant (p<0.05). In two groups MMSE scores, P300 latency and P300 amplitude was significantly improved after treatment compared with those before treatment (P<0.05 or P<0.01). The improvement in the treatment group was better than that in the controls. Conclusion: Naomaitai capsule for treating vascular dementia shows good efficacy and less adverse reactions. The capsule can promote cognitive recovery.