Abstract: In order to study the influence of transition on the aerodynamics of a supercritical wing, both free transition and fixed transition conditions were simulated on the basis of the three-dimensional Reynolds-averaged Navier-Stokes(RANS) solver with a transition prediction method based on the e^N-Database. The calculated results are consistent with the experiment data, which indicate that the numerical methods are reliable and feasible. According to the numerical results, the shock wave moves forward along the upper surface of the wing followed by forward moving transition point at the constant angle of attack(AOA), leading to an decrease in lift coefficient due to the reduced area of supersonic flow. The pressure distribution with free transition of the wing section changes from a flat to a peaky type at AOA between 1 and 1 degree at Ma=0.8. This change causes the transition point moves forward rapidly, and the approximate linear relation between the lift and the AOA is lost.