Abstract: With the increase of refracturing amount in various Oilfields, a mechanical model of optimal timing for refracturing on solid-fluid coupling was established, and a finite element simulation software was developed with Fortran95 to describe the stress variation with time at different point and study optimal timing for refracturing affected by multi-factors. Results indicate the coupling model considering interaction between two important process of solid deformation and fluid flow is closer to actual situation. The optimal timing for refracturing is determined by several formation parameters together, responding to time when distance of equal stress point approaches a certain value. Field examples show that the application software has high reliability of computation accuracy, complete function, and strong pertinency.