ABSTRACT This report provides a new gel profile modification agent prepared by a amphoteric copolymer (FT—213) and a nevol crosslinking agent (BY), and introduces the preparations of the amphoteric polymer, the crosslinking agent and the profile modification agent, the action mechanism, the conditions testing and the evaluations of the performances of the agent. The 45 well treatments in oilfields demonstrate that the agent can be prepared convienously, the agent has better compatibility and application performances, and the treatment life by using the agent is longer. 80000 tons increamental oil and 60000 m* decreasing water production have been achieved.