Abstract: Because of polymer plugging, polymer injection well stop injecting or inject unefficiently and the liquid decreases in Gudao oilfield. To solve this problem, the authors develop an efficient polymer blocking remover DOC-8, which not only can break down polymer plugging but also have strong restoring force for the cross-linked polymer plugging. In the meanwhile, the authors find the acid treating agent JNC-006 can break down the plugging of clay and mechanical admixture. This technique can further increase the effect of polymer blocking.