Abstract: Fault movement has a complex and variable pattern and one segment of a great faultzone is usually a unit of rupture. In order to meet the needs for major engineering projects and strong earthquake predication, It is necessary to lacate which segment of a fault zone is active. We propose in this paper that the movement of middle segment of Xiangshan-Tianjingshan fault zone is mainly stick-slip and both its eastern and western segments show mainly stable-slip. On the basis of microstructural characteristics of fault gouge and the segment geometry.