The objective of this project is to define a methodology for the design and analysis of multistage axial-flow compressors. A numerical methodology is adopted for optimizing the efficiency at the design point of a fifteen-stage axial-flow compressor with inlet guide vanes (IGV). The calculations are carried out along the mean streamline using the principals of thermodynamics and aerodynamics. A computer program was developed that simulates the compressor model. By specifying the geometry specifications (tip clearance, aspect ratio, thickness-chord ratio, blockage factor, etc.) and design parameters (mass flow, rotational speed, number of stages, pressure ratio, etc.), an accurate numerical model can be generated. This modeling technique is much simpler than the usual computational methods that need much more modeling/programming effort and computer run-time. Starting from a newly-designed axial-flow compressor, an optimized version is obtained with improved design-point efficiency. So, once we get the optimized geometry of the compressor, the original geometry is altered to maximize the efficiency at the design-point. Concerning the optimized version, analytical relation between the isentropic efficiency of the compressor and the flow coefficient, the work coefficient, the flow angles and the degree of reaction are obtained.