After a period of time of production, in some wells, the crude oil at the old crack has basically been taken out, but there's certain amount of recoverable reserves. In order to improve the efficiency of these wells, refracturing is required. Temporary plugging agent in refracturing plays a very important role; it is the key to the success of refracturing. In this article, a new kind of temporary plugging agent has been developed, we have done lots of laboratory testing researches about its performance and temporary plugging effect. And, nonlinear finite element numerical simulation analysis has been adopted for temporarily blocking crack and the impact of the wells. It is can be seen from the experiment and finite element analysis that the new temporary plugging agent has a good effect; it has no secondary pollution of wells. Temporary plugging agent can provide protection for wells, and it has a good prospect.