Abstract: The flow over multi-element airfoils has been numerically investigated in ansys fluent and has been compare the aerodynamic parameters with the standard NACA airfoils 4412 and 0012. The 2D viscous, transient, pressure model equations together with the k-ω turbulence model were applied to this numerical simulation utilizing the multi-block unstructured grids of sphere of influence type. Numerical results showed that the aerodynamic parameters of multi element airfoils with tail effect is much optimum than the standard naca airfoils. Also the analysis is made on different flap and slat angles of different conditions and the optimization of multi element airfoils has been performed.