Abstract: Unstable behavior of an axial flow single stage compressor has been researched successfully by use of a simple dynamic measuring system.The character and the influence factors of the unstable behavior have been analyzed from systematic view.The experimental results demonstrate that the unstable types of the compressor could convert each other in certain conditions.The compressor rotor speed,the construction and size of the exhaust parts are the main factors influencing the convertion.The surge occurs in the compressor on condition of high rotor speed or large exhaust volume,otherwise the rotating stall appears.The decrease of the exhaust volume leads to increment of the surge frequency.There is an obvious difference of the unstable behavior between the single stage compressor and the isolated rotor compared.In the condition of high rotor speed ( >0 85),a stall phenomona of nonrecoverable stall appears.It's character is also considered.