By comprehension of the focal mechanism solutions of earthquake and the data of the measurements of the in situ stress, the tectonic stress field in Shanxi region was summarized, which indicated that the stress state in this region was so different from that of the surrounding regions. The next, by fitting of the measured data, the boundary force which influenced the distribution of the stress field in this region has been studied using the inversion method. The result of the inversion showed the distribution of the stress field in this region and it’s influence factors clearly.