The limited number of natural cores obtained by drilling and sampling results in great discreteness in experiment results of indoor physical and mechanical tests. Reservoir rock mechanical parameters are hard to be determined accurately.Therefore，according to physical mechanical experiment results of cores and reservoir porosity at various burial depths interpreted by logging data in certain oilfield，a finite element analysis software RFPA2D was applied to build corresponding numerical simulation cores using numerical simulation method. The Young’s modulus，stress peak strength，residual stress strength，Poisson’s ratio and other rock mechanical parameters of cores with different porosities were analyzed. Regression analysis was done on the physical and mechanical experiment result and numerical simulation results. A prediction model was built with porosity as the main variable. Based on the prediction model，three-dimensional hydraulic fracturing model of the reservoir in certain oilfield was built and the configurations of the features were discussed. The fracturing curves predicted by the numerical simulation and those from the field operation were compared. It is shown that there is a good agreement between the simulation result of fracturing pressure and the actual one and there are few differences between the two in initiation pressure and propagation pressure of the fractured interval. The results and the method are rational and available.