To solve the problem of polymer plugging of polymer injection well area in the bohai sea, a kind of efficient composite depolymerization additive is screened in the paper. Laboratory experiments show that the degradation rate of 5 000 mg/L polymer solution can reach more than 99%, and the polymer scale samples with crude oil from oil well in Bohai can be degraded in 72 h because of the low interfacial tension and good oil washing effecthigh effect of washing oil. Meanwhile, the high chelating ability of this depolymerization additive is good for the depolymerization of the crosslinking polymer, and the degradation progress can be as less as 3 h.The plug removal application in one oil well well shows that the efficient depolymerization additive has remarkable capacity of enhancing liquid and oil.