Abstract: When the oil well is produced by polymer flooding, it contains polymer, which lead to difficulties in crude oil dehydration and sewage disposal. Present situation of dehydration and emulsion breaking of polymer flooding produced liquid was analyzed, then based on the effect of structural cracking and structural recovery behavior of crude oil emulsion gels on its thixotropy, polyether type emulsion breaking agent produced by using the reaction product of poly ethylene polyamine, rosin amine, organic aldehyde, amine, phenol as initiator, was formulated according to a certain proportion, then by introducing micro alkyl amide betaine, ferrous chloride, vitamin C, fluorocarbon surfactant FN-3, the low temperature demulsifying agent for dehydration of polymer flooding crude oil produced liquid was finally obtained. By using the electric neutralization mechanism, the low temperature demulsifying and dehydration were implemented for crude oil produced liquid by polymer flooding. In the field, the dosage was 50-70 mg/L, dehydration temperature was 40-43 ℃, the water content of crude oil was less than 0.2% after dehydration and the oil content of sewage was less than 50 mg/L.