In this study, an automated optimization tool for angel of variable stators in multistage compressors has been developed. Performance of the compressor is estimated using FORTRAN program coding based on streamline curvature method. Genetic algorithm is used to handle optimization processes. To demonstrate feasibility of the present method, a 10-stage compressor was optimized to maximize its total pressure ratio of operating point in off-design conditions. The variable geometries that were studied in this paper are: (1) VIGV; (2) VIGV and first row variable stator; (3) VIGV, first and second rows variable stator.