The mathematical model of plasma flow control is established by regarding the influences of the plasma aerodynamic actuation on the fluid as body force and thermal energy and considering the influences of the plasma temperature rise on the thermal physical property of fluid. The body force and thermal energy profile function obtained by solving the potential equation and the charge equation and the thermal physical property function obtained by fitting experimental data are added to the Navier-Stokes equation as source terms and coefficient respectively. Simulation investigation of flow separation control on a compressor cascade by plasma aerodynamic actuation is performed under low velocity conditions. The influence of the flow velocity, incidence and the intensity of plasma aerodynamic actuation on the performance of compressor cascade is investigated. After actuation in the case of [WTBX]Ma[WTBZ]=0.05 at an incidence of 2°,the location of separation point is moved from 65.09% to 79.4% of the chord, the flow turning angle is increased about 1°, the maximum total pressure loss coefficient is reduced about 7.4% and the width of the trail is reduced about 12%. The actuation effect is reduced with the increase of air flow velocity. The change of incidence affects the actuation effect. The actuation effect is obviously improved with the increase of the intensity of plasma aerodynamic actuation.