Abstract: According to the specialties of fracturing reservoirs in Jilin Oilfield, the study is researched a compound profile modification agent, called NK, which has the bi-characters of plugging fractures and filling base rocks. The study investigates the gel strength and gelling time effects caused by polymer ion activity, crosslinker concentration, grain volume, temperature and water quality. It also compares NK compound modification agent with complexing chromium modification agent and surface filling grain agent in intension, filling ratio, break pressure and flooding endurance. The result shows that NK is prior to another two agents in any characters. This kind of agent is applied for fracturing reservoirs with the great profile modification effects.