An adaptive treatment casing with annular cavity guide vane was designed. The influence of different guide vanes on the flow field of subsonic multistage axial compressor was studied by means of steady numerical method. Results showed that when the guide vane perpendicular to the rotor chord wise weakened the leading edge overflow intensity of the blade tip

the treatment casing restrained the development of clearance leakage flow

improved the flow capacity of the rotor blade tip passage

and made the compressor basically unchanged while the speed characteristic was above 0.8 design speed

the stability margin of low speed was greatly improved

in which the total pressure ratio at the near-stall point increased by 10.2% at 0.7 design speed and the near-stall flow rate expanded by 8.5%

showing the strong adaptive stability-expanding ability.