Abstract: A model for predicting the effect of inlet steady state circumferential total pressure distortion on compressor stability pressented in reference [1] has been improved by considering the variation in compressor efficiency due to the distortion.The impr oved model is applicable to case of the inlet steady state circumferenti al total temperature distortion.Based on this model,a method has been dev eloped for estimating the effects of combined pressure and temperatur e distortions on the compressor stabilit y.A numerical analysis was conducted for a two spool turbojet engine with the pr essure and temperature distortions as we ll as the combined distortions.The results show that the variation in compressor efficiency due to distortion cannot be negligible for large amplitu de pressure distortion.For the combined distortions,the pressure and temperature distortion orientations play a certain role in the compressor stall.The maximum loss in the compressor stall margin occurs at superimposed (180° overlap) combined distortion.Conversely,the effect is minimum for the opposite combined distortion.