The present invention is nuclear membrane structure demulsifier for the demulsifying treatment of tertiary oil extraction effluent. The application of tertiary oil extraction technology, especially the injection of polymer, increases the raw oil yield obviously but increases the viscosity of raw oil and the demulsification difficulty. The present invention features that the nuclear membrane structure demulsifier consists of demulsifier containing propylene oxide and ethylene oxide embedded polyether, nucleating nanometer particle material containing aluminum salt, ethyl silicate, butyl titanate or others, and ammonia water as reaction and aminolysis solvent. The present invention may be used in demulsifying the effluent of tertiary oil extraction effectively in lower consumption, fast demulsifying speed, high dewatering efficiency and regular oil-water interface.