The flow field between two rotors under the rotating-speed difference in the counter-rotating compressor will affect the compressor performance.In this paper,some rotating-speed differences are measured and tested on a dual-stage axial counter-rotating compressor by using the particle image velocimetry(PIV) technique to describe the rotor-rotor interaction of flow field structure.The results of analysis show that the unsteady flow fields under the different rotating-speed differences and phases are varied e...