Abstract: As a case study of ZHI block in Zhunggar basin, a new method of multistep constraint stochastic modeling was presented, which integrates together geology, well logging and seismic data. The multistep modeling method can properly solve the problem that simulation target value and restriction value have no perfect relations, for example, facies and impedance. The method of multistep modeling has three steps. Firstly, the random field of typical geophysics curve, constrained by impedance data, is built by Collocated Cokriging simulation. Secondly, based on the geophysics curve field realizations the facies models are built. Finally the reservoir parameters model is built using Sequential Gauss simulation, constrained by the reasonable facies model which is picked through facies simulation realization analysis. This method has good performance in the phase of pre-development.