Abstract: In order to study the aerodynamics of the airfoil based on plasma circulation control, the Reynolds average N-S equation and mathematics model of plasma excitation based on phenomenology method are used, and the change characteristics of lift affected by the trailing radius are simulated, the optimum radius is determined. Through the low speed wind, the experiment is conducted at the angle of attack of -4 to 12, and at the speed of 6 m/s, 10 m/s, 15 m/s. The pressure distribution and lift coefficient are obtained. The results of the simulation and experiment show: it is unfavorable for the formation of Coanda effect with too large trailing radius or too small trailing radius, and the optimum ratio of radius and wing chord is 0.048, with the efficiency-cost ratio up to 97.69. The laminar separation of long bubble and short bubble appears with the increase of the angle of attack at low Reynolds number. The influences of plasma jet not only include the tail flow field, but also include improving laminar separation based on the increased circulation, and increasing the lift.