Abstract: By using of paleo-tectonic stress field in two-dimen-sional numerical simulation,this paper predicted the extent of the rupture of rock of the study area and classified the coefficients of cracked approximation degree of the rock,deter-mined the relationship between the coefficients of cracked degree of the rock and fracture,the developmental level of fracture,and gave a general prediction to the fracture growth,types and azimuth of fracture.The prediction result shows that fractures in YingCheng reservoir are more devel-oped in fault and nearby ;two stages'(four groups aggre-gately)fractures,which categories are mainly early stage and late stage.main extensional directions of these fractures are SN,NE.