Abstract: To determine the reason why the single lunette-shaped flat baffle is used for inlet total-pressure distortion assessment regulated in GJB/Z64-2004(K),validity research was carried out experimentally for four kinds of flat baffles in the two-stage low-speed axial compressor,and complex distortion descriptor characteristic was compared in detail for each flat baffle.The experiment results indicate: outcomes adopting single lunette-shaped flat baffle tend to be conservative and rigorous,time-variant distortion descriptor and steady-state distortion descriptor are equivalent in the proportion of the complex distortion descriptor,and flat baffle experiment can bring great enough time-variant distortion.