Abstract: In recent years, a large number of dolomite lithologic gas reservoirs have been found in the middle part of Ordovician strata in the Shanbei loess tableland. Nevertheless, the surface conditions of this area are complex, which leads to a poor seismic data imaging accuracy, and the main reservoir Mawu5 Formation of Ordovician is characterized by extensive distribution,thin reservoir,strong hetero?geneity and drastic lateral variation in physical properties, which results in more difficulties in seismic prediction. With the 3D high?fi?delity seismic data of 600 km2 collected in the Shanbei loess tableland in recent years, technologies of FFP analysis and function formu?la between the elastic parameters fitted by drilled wells were applied innovatively based on an analysis of rock physical sensitive factors and the strengthening of pre?stack inversion. The dolomite probability, gas probability, porosity and gas saturation of Ma55 Formation in the project was calculated. The favorable gas area in the dolomite reservoir of Ma55 in the Su203 well district was described clearly, and then the favorable drilling targets were evaluated and obtained, thus achieving good results.