Abstract: Practicable loss and deviation models fortransonic and subsonic axial compressors are established. They are combined with the blade row-by-blade row cascademodel. A method for calculating off-design performance of multi-stage axialcompressors is developed, based on those models. Box's optimizationtechnique is then used to optimize the stator vane stagger setting. Themethodology has been incorporated into a computer program and isvalidated by usingdata from an eight-stage transonic axial compressor. Resultsshow that the variable stator stagger setting is a powerful method torematch stages, which can be used to enlarge aerodynamic stability range ofmulti-stage compressors.