Abstract: A large scale axial flow compressor research facility designed for relative flow measurements is presented.With the test section outer diameter of one meter and hub/tip ratio of 0 6,the facility has a unique rotating probe traversing mechanism downstream the rotor blade row and inside the hub,which is capable of traversing five hole pressure probe,hot wire and other probes across the rotor blade passage.The precise null,tangential,radial and axial motions of the probes are entirely electrical and controlled by an online 386 microcomputer.The data transmission system which transmits signals from rotating frame to stationary frame of reference consists of rotating Kulite pressure transducers and a multi channel slip ring.In stationary reference frame,where the velocity and pressure at the rotor exit are unsteady with both periodic and random components,high response probes fixed on stationary probe traverse mechanisms are used for rotor exit flow measurements.Two high frequency pressure probes(a two inclined hole probe and a four hole conic probe)have been developed and two hot wire techniques(a single slant hot wire and a two inclined hot wire sensor)have been improved.A self made computer controlled 16 channel parallel data acquisition and processing system with the maximum sampling frequency of 100KHz per channel,accompanied with a phase locked ensemble averaging technique,is used for acquiring the data measured by high response probes.Typical data on the three dimensional flow structure at the rotor exit and inlet with fine resolution by various probes are presented.