Abstarct: The study area located between binalood mountain range and mashad plain, between the border of oltrabasic, apilits and mextamorphic rocks with Paleozoic age with quaternary sediment. In this area, mextamorphic rocks, ophiolits, some equivalent lar formation and quaternary sediments affected by south mashhad- chenaran fault system with 150 Km long. Field stress analysis of area show that main stress field of study area is NE-SW. We use from structural element of area and stretch line of faults and analysis with wine-Tensor software to reach this results. With stress field analysis of south mashad - chenaran fault system and with consideration of main stress field of area and also stretch line of south mashad-chenaran fault system, NE-SW trend and right lateral mechanism with some reverse with northward dip for this fault recognized. Reverse mechanism for this fault show compressional regim in investigated area. With consideration of filed evidence and neotectonic structure of study area in fans, cutting and right lateral displacement of waterways confirmed our results. Finally we propose name of this fault change to south mashad- chenaran fault system.