In modern military aircraft engines, the stable flight envelope is limited by the compressor surge which is an unsteady working condition affecting both compressor and receiving circuit (i.e. all engine components). This obliges the engine designers to provide for a "SURGE MARGIN" i.e. a limit of the working domain excluding this instability. The choice of this stability margin must be wade during preliminary design and design stages considering both global design parameters and fine costruction elements. The modern design techniques must take into consideration not only the cnal geometry and the axial load distribution between compressor stages, but also the radial load distribution on each stage. In addition to these global design parameters we discuss also in this paper the effect of fine construction elements such as nominal incidence, tip clearance, blade aspect ratio, stage solidity, casing treatement, bleeds and variable geometry.