When two airfoils are moving in a complex way, the wake of the before airfoil has a great influence on the movement of the after airfoil. The scenario studied in this paper is that two NACA 2412 airfoils are oscillating while making a sinusoidal motion, they have the same sinusoidal motion frequency and oscillation frequency. ANSYS CFX was used for numerical simulations to study the effect of the before airfoil on the after airfoil. The distance between the two airfoils affect the two airfoils’ movement are discussed and compared. Finally, some results of the setting conditions are showed. The pressure contours, velocity vector illustrations and picture of lift coefficient and drag coefficient show some valuable information.