Determining the stratum fracture as an essential approach to the field of prospecting oilgas and engineering detecting based on P-wave is very difficult. Seismic wave field is complicated in the isotropy medium where there are some fracture because of the scattering.To recognize seismic wave character in the fracture stratum, this paper deals with the simulating seismic record of the fracture medium and uniformity stratum based on sound wave equation and by using high order finite difference method for improving precision. Meanwhile, it analyzes the change of the characters of seismic wave field in the strap of fracture growth. Results indicate that it is feasible to detect the fracture by dynamics characters of P-wave.