Abstract: Stress strain environment of perimeter faults of Chaidamu Basin was deeply researched through analysis of super microstructure of the faults.The research results showed as the following.Flat and straight dislocations of lower density of super microstructure are typical feature of Xingaoquan fault and reflected relatively lower environment of stress strain.The Datouyang fault is characterized by high dislocation,complex dislocation shape,which stretched meanderingly and developed circular shaped dislocation locally.All of these reflected that stress strain environment of Datouyang fault is higher.The remarkable character of Luliangshan thrust is sub grain developed universally,which indicates strain environment getting into recovery stage.The super microstructures of Nachitai thrust are more complicated.Development of different degree of dislocation,dislocation wall and sub grain showed complex of deformation.According to characteristics of super microstructures,the paleostructure stress and strain rates are also calculated.