The modern characteristics of distribution of the tectonic stress field in the northern part of North-south Seismic Belt are studied in this paper with distortion analogy,ordenary optic elastics and the simulated test of optic elastics of laser holography under various force sources.The paper deals with the principal compression stress,the main tension stress and their directions in this region.The isorithm of the principal compression stress in the region is given in this paper as well.Thus it can be known from the test mentioned above the stress value in the action of unified stress field in every segment of this region.With Moll strength theory,the seismicity here is made an analysis and a research is conducted to the.relation between the modern features of distribution of the tectonic stress field and epicentral migration.