Organic materials of D-π-A type MR-X (MR-1:p-dimethylaminophenylethenetrica-rbonitrile and MR-2:p-diphenylaminophenylethene tricarbonitrile) were designed and synthesized.The device with a sandwich structure shows good rectificative phenomena.The highest rectification ratio 10000 was achieved in device Cu/MR-1/Ag,and about 100 in other device M/MR-X/M (M:Cu,Ag).It has been found that rectificative phenomena exist only in the atmosphere-liquid interface region by means of liquid adsorption,and electric field could help form the oriented molecular film.