Abstract: Compressor characteristics maps need to be interpolated and dispersed during gas turbine engine performance simulation.Meanwhile the maps usually need to be extrapolated as the characteristics data of low rotational speed are absent.An improved method of using dimensional surface to illustrate compressor characteristics instead of rotational speed lines was proposed.Characteristics data were calculated from start-up test results of a small gas turbine engine.Based on these data and the known characteristics data from the original map, a characteristic curve was generated using moving least square(MLS).The generated curve covers all the operational range and has a high degree of accuracy.It is very suitable for performance simulation as it need no interpolation.