Abstract: Abstract Onset points of rotating stall,time average performance and flow fields after stall appearing,as well as the unstable behaviors for a single stage axial flow compressor and an isolated rotor have been measured successfully with hot film probes and a three hole cylindrical pressure probe containing fast response transducers.On the basis of many experimental data,the influences of stator cascade in the single stage compressor on the whole time average characteristics and the cessation behavior of rotating stall,as well as the stalled flow field have been elaborated in detail.When a single stage compressor enters the unstable condition,the roles of the stator cascade,such as postponing the appearance of rotating stall,as well as modifying the stalled flow field and cessation form,have been analysed.There is an obvious difference of the unstable behavior between the single stage axial flow compressor and the isolated rotor.At high rotor speed (>0 85),a nonrecoverable stall phenomenon appears for a single stage compressor,but it does not appear for an isolated rotor at any speed.