For a centrifugal compressor, as a result of the relative motion of static and dynamic blade rows, it will cause the rotor-stator interaction induced by the airflow in the compressor, to produce the unsteady airflow exciting force and the high amplitude pressure pulsation. The unsteady rotor-stator interaction has an important influence on the stability, normal operation and practical efficiency of the compressor. In order to effectively study the signal characteristics of rotor-stator interaction, the operational modal simulation calculation for the impeller of a model centrifugal compressor test rig is carried out to obtain the impeller interferogram, and determine the speed conditions at which the inlet guide vanes (IGV) or the outlet guide vanes (OGV) has interference to the impeller. Finally, a strain test and a pressure fluctuation test are carried out under the determined experimental speed conditions. Through the analysis and comparison, the existence of the interference characteristic frequency under the simulated rotating speed conditions is verified, and the strain signal is also proved to be more suitable for identifying the characteristics of the interference signal. Through summing up the relationship between the interference characteristic frequencies of the serious interference speed conditions and the natural frequencies of the impeller, it lays the foundation for further improvement of centrifugal compressor.