Abstract: Polymer flooding has become one of the most potential EOR methods both at home and abroad. A large amount of polymer has been injected during polymer flooding, resulting in the plug in the area near well bore, and decreasing in the subsequent polymer and water injection. In order to solve the problem of well plug during polymer flooding, DJD-A composite depolymerization agent has been screened in the laboratory. The water injection rate has been increased greatly after application. The successful application in removal of polymer plugging will provide beneficial reference for plugging removal during the same type of polymer flooding.