Increasing the pressure in gas turbine cycle is done by Compressor which is one of the most important components of the Gas Turbines. Due to positive pressure gradient, the nature of the flow inside the compressor is complicated and for this reason and because of the duty of the blade for transferring energy to the flow, precise design of the compressor’s blades from the aerodynamic view of point is very important In this study, effects of changes the rotor blade stagger angle on a transonic axial compressor performance curves including efficiency and pressure ratio has been studied. To simulate the complicated three-dimensional flow field in axial compressors, a numerical code is used to solve Reynolds Average Navier-Stokes (RANS) equations. comparison between numerical results and experimental data shows a good agreement. When numerical code are verified. Then the rotor blade twist changes on axial compressor performance have been studied. The results show that the rotor blades twist leads to decrease in compressor efficiency and pressure ratio.