Abstarct: For analyzing, designing and forecasting of structure proceeds which construct in or on the rock masses, need rock mass geomechanical properties understanding like resistance, flexibility, cohesion and friction angle. In this research first due to numerous joint set existences in upper reservoir pumped storage power plant of Azad dam place and also dip of different slope geometry, probability failure types in reservoir have been identified. Then instrument data in northeast reservoir origin (faulty area about 400 meters) has been studied and also back analysis technic utilizing, rock mas geomechanical parameters such as deformation module, cohesion and friction angle e values of their 1Gpa, 127Kpa and 35 degree determined. Reservoir parameter which obtained with doing back analyzing can used as input parameters to stability analysis, support system optimum to stability analysis, support system optimum designing, deforming of support system safety and etc. In next step from analysis method for danger evaluation has been used. According to analysis done kargine fault with 7.3 in Richter scale as dangerous fault in study area was recognized. Finally whit dynamic analyses of mentioned reservoir, displacement and strain of slope different points of probability earthquake occurrence have been studied. The results of the dynamic analysis shows in the part of Northeast upper reservoir (faulty zone, which is the most critical zone in reservoir area) Horizontal displacement in the direction vertical the bench of the slope in a second stair of the critical points 20 cm and vertical displacement 5 cm appears is reached by Investigating the graph of shear strain in some parts of the second stair, the strain 0/06 Reaches, According to the this results in some parts of the reservoir will be Instability