Due to the high permeability and the development of high-capacity channels in offshore oilfields，it is difficult for the conventional plugging agents to meet the technical and economic requirements of plugging. In order to solve this problem and plug the highly permeable layers effectively，the composition of plugging agent was optimized and its influencing factors were studied through experiments under the reservoir temperature condition based on the reservoir characteristics and fluid properties of Bohai Oilfield. Physical simulation and instrument testing was done theoretically guided by inorganic chemistry and reservoir engineering. Considering the curing time，the acid solubility and the compressive strength of the plugging agent，NaOH，inorganic tackifier and compound retarder were recommended as the best choice for the curing agent，the tackifier and the retarder. The influence of retarder on the curing time of the plugging agent is the most obvious compared with the components of tackifier，curing agent，retarder and main agent. When the concentration of retarder is from 0.1% to 0.5%，the curing time ranges from 5.5 hours to 480 hours.