To address the issue of the stable oil-water "transition layer" in polymer flooding produced fluid，which is formed by the synergistic effects of resins，asphaltenes，mechanical impurities，and polymers，the composition of the transition layer was analyzed and the inhibition mechanism of its main components on the electric dehydration process was revealed. A synergistic treatment scheme combining an electric field and chemical agents was proposed，and its electro-chemical synergistic destabilization mechanism was demonstrated. The results indicated that the SYP- 416 with a mass concentration of 500 mg/L had a significant effect on treating the "electric field collapse" phenomenon caused by solid phase，reducing the water content in the oil to 1 . 36 % after 1 hour of electric desalination. The SYP- 417 with a mass concentration of 500 mg/L had a relatively obvious effect on treating the "electric field collapse" phenomenon caused by oil phase，reducing the water content in the oil to 2 . 31 % after 1 hour of electric desalination；while the compound agent （mass ratio of SYP- 416 to SYP- 417 being of 1 ∶ 1） with a concentration of 500 mg/L had a remarkable effect on treating The oil sample of the transition layer on site，reducing the water content in the oil to 0 . 96 % after 1 hour of electric desalination. The compound agent could effectively address the issue of "electric field collapse" in the electric dehydrator caused by the transition layer. The current had significantly decreased，and the synergistic mechanism between the chemical agent and the electric field had significantly enhanced the mass transfer efficiency of interface water molecules and solid particles，achieving efficient demulsification and separation. The field application results confirm that the technology can restore the operation stability of the electric dehydrator.