Abstract: A pitot pressure pulsation generator and a data acquisition and processing system have been built up for this research.The response of a low pressure compressor to two kinds of inlet dynamic flow modes (axisymmetric or distorted) are investigated under the conditions of the compressor with or without a plenum.The results show that there is a sensitive frequency at which the perturbation is amplified through the compressor.The sensitive frequency is influenced not by inlet distortion,but by the plenum in the present research.