Abstract:Luohu Fault Zone is a part of Shenzhen—Wuhua Fault Zone and composed of 13 faults trending in NE direction and 6 faults trending in NW direction in the area of 38 km2,where faults are very dense. This fault zone is inside of Shenzhen City where many tall buildings locate,and F8,a fault of Luohu Fault Zone,is an active fault which acted in 1994. So it is very important to study the crustal stability of this fault zone. The geologic conditions of this zone are introduced firstly,then the 3D geological model is built and the numerical modeling of geostress field is finished with the elastoplastic finite element method. According to the modeling results,the characters of the geostress and the influence of the faults on the geostress field are expounded and the tectonic stability of the area is analyzed. The study shows that these faults have remarkable effect on the magnitude,direction,continuity and concentration degree of the geostress,and the tectonic stability in a few sites is bad because of the existence of plastic failure zone. It is very serious in the area which is be enclosed by F8,F13,F205 and F206,because the plastic failure can induce the stress relief and the decrease of the stress concentration degree,the main action manner of the faults is creeping slide and middle or strong earthquake will not happen.