Abstract：In order to inspect the change form of schema transformation and the stress form of Hetao seismic stress field, we use amplitude ratio and CAP methods to calculate 224 focal mechanism solutions, based on normalized frequency statistics and analysis of fault slip type.The results show that the advantage distribution of compressive stress orientation is NE, the advantage distribution of tensile stress orientation is NW, and the rake angleis distributed nearly horizontally. Further, the whole stress field shows inheritance features, horizontal shear and tension control the stress form of faults in Hetao seismic belt, and the main outputs are strike-slip type earthquakes. Throughout the whole study period, a steady stress model is presented. Combining peripheral dynamic properties withregional tectonic movement determines that, under the joint action of the westward subduction of the Pacific plate and the Qinghai-Tibet block northward migration, Yinshan uplift and Ordos block relative to do spin twist.Finally, the NE-EW distribution faults present horizontal and rotary shear, and constitute a relatively stable evolution model of stress field.
