Objective To observe the effect of electroacupuncture(EA) therapy of activating Du meridian,regulating mind and reinforcing the fundamental on learning and memory ability and plasma endothelin(ET) level in rats with vascular dementia(VD).Methods Healthy adult SD rats were randomized into pseudo-operation group(N=8),EA group(N=9,EA on the acupoints of Baihui,Dazhui,Pishu and Shenshu),nimodipine group(N=8,at the dose of 12mg/kg) and the model group(N=8).Rat models of VD were established by the modified 4-vascular occlusion(4-VO)method.Morris water maze test was used for the behavioral observation,and plasma ET level was measured by radioimmunoassay(RIA).Results Plasma ET level was increased obviously,the disorder of learning and memory ability was obvious and the escape latency in water maze was prolonged in the model group(P0.05).In EA group and nimodipine group,the escape latency was shortened(P0.05 compared with the pseudo-operation group).Conclusion The therapeutic mechanism of EA therapy of activating Du meridian,regulating mind and reinforcing the fundamental for VD is probably related with the regulation of plasma ET level and with the increase of learning and memory ability.