Abstract: Detailed measurements of three dimensional turbulent flow field at exit of an axial flow single stage compressor and downstream were made in different mass flow conditions.The flow structure was surveyed with both hot wire probe and high frequency pressure probe.The results show that in design condition,substantial blockage,loss and turbulence mainly exist in the tip mid passage,wake and the corner between the suction surface and the hub as the mass flow reduces,the high turbulence areas enlarge with the flow structure changing,and the flow becomes more turbulent.Distributions of three turbulence intensity components are almost similar,and the radial component is found to be the highest,while the axial radial component of Reynolds stresses is the largest.In the downstream flow the decayed tip leakage vortex moves toward the pressure surface and the low radial location and leads to more flow mixing,blockage and turbulence in the tip region.The rotor wake becomes wider while the flow loss increases.Both radial velocity and radial turbulence intensity decay obviously,and the axial tangential component of Reynolds stresses is the largest.Vortex is one of the most important factors which cause the pressure fluctuation and airflow noise.