Objective To built up the ERP model,measure mode and P300 potential reference standard in mice with vascular dementia(VD),and characterize the P300 potential in mice with VD.Methods Fortyeight mice were randomly divided into a normal group.sham operation group and a VD group.The mice in the Vd group were subject to repetitive ischemia and reperfusion by using the ligation of bilateral common carotid arteries so as to establish the VD model.The behavioral abnormalities were investigated by step-down test and water maze test.The N2 and P3 components of P300 potentials were also recorded.Results It was shown that the learning and memory abilities as reflected by the step down test and water maze test scores were decrease in mice in the VD group when compared with those in the normal group and sham operation group(P<0.05).The N2 and P3 latencies significantly prolonged(P<0.01)and P3 amplitudes decreased(P<0.05)in VD group as well.Conclusions In VD mice,there is a significant prolongation of the P300 potential latency and a significant decrease of learning and memory abilities.Recordings of P300 from unanesthetized mice could be an objective,non-invasive,quantitative and valuable electrophysiological method for studying the cognitive function of VD mice.