To evaluate the effect of Dengzhan Shengmai Capsule on vascular cognitive impairment(VCI)and explore its possible mechanism.Methods:A total of 130 cases of VCI patients first diagnosed in our hospital during December 2015 to July 2018 were divided into control group and Dengzhan Shengmai Capsule group each with 65 cases by random number table method.Patients in control group were treated with routine western medicine treatment，those in the Dengzhan Shengmai Capsule group added Dengzhan Shengmai Capsule on the basis of control group.The curative effect was evaluated after 3 months of continuous treatment.The differences of cognitive function scale score，TCM syndrome score，vascular endothelial function indexes［Endothelin-1(ET-1)and nitric oxide(NO)］，oxidative stress indexes［Superoxide dismutase(SOD)，glutathione peroxidase(GSH-Px)，malondialdehyde(MDA)］ and adverse drug reactions between two groups were compared.Result：After treatment，score of MoCA in Dengzhan Shengmai Capsule group was higher than those in control group，while score of SDSVD in SDSVD group was lower than those in control group; scores of TCM syndromes such as mental decline，slow reaction，dizziness，tinnitus and dementia were lower than those in control group; serum content of ET-1 was lower than that in control group，NO was higher than that in control group; serum contents of SOD and GSH-Px in serum were higher than those in control group(P<005).There were no significant difference in the incidences of skin rash，diarrhea and constipation between two groups(P>005).Conclusion:Dengzhan Shengmai Capsules can effectively improve the cognitive function of VCI patients and has good drug safety.Its mechanism may be related to the regulation of vascular endothelial function and antioxidant stress.