Abstract: On the basis of analysis of the development of grabens, seismogenic faults and focal mechanism, the nature of changes of tectonic stress field in the eastern part of North China during Early-Late Tertiary is studied in this paper. The region under investigation was subjected to a strong NW-SE tension in Early Tertiary. Since Late Tertiary it is mainly controlled by the NE-NEE compressive stress field with the NW-SE running tensile stress field in subordinate place. The stress field here has been affected by the action of the Pacific plate in Early Tertiary and by the action of the Indian plate since Late Tertiary.