Abstract: To reduce the leakage of workover fluid and prevent the formation damage, using the shielding temporary plugging theory in drilling process, this study put forward the plugging materials self-match plugging technology for workover treatment. For this technology, weak gel suspension was prepared, and a polymer material was synthesized as a key material for plugging, characterized by good viscoelasticity, high deformation degree, high strength, water swelling and automatic hydration degradation at a certain temperature. Moreover, this material can collaborate with other auxiliary temporary plugging material to form a workover plugging system including gel, self-degradable material, oil soluble resin and micro bubble, able to form a plugging barrier in the leakage layer and effective to reduce the leakage of workover fluid. The performance evaluation results show that this system has a bearing pressure of 15 MPa, the ability of automatic degradation in 3-5 days, and the permeability recovery rate of over 90%, able to achieve the purpose of blocking, plug releasing and less reservoir pollution. The application of this system is over 52 well times in Dagang Oilfield, and a high plugging success rate greater than 95% is achieved for the wells with permeability, micro fracture and big-pore-throat leakage loss or the coexistence of multiple leakages. The average yield recovery period of the well is less than 5 days, and the average yield recovery rate is more than 97%, indicating the significant protection effect on oil reservoir.