The present study numerically investigates the aerodynamic characteristics of two-dimensional wings in the vicinity of the ground by solving two-dimensional steady incompressible Navier-Stokes equations with the turbulence closure model of the realizable k-${varepsilon}$ model. Numerical simulations are performed at a wide range of the normalized ground clearance by the chord length ($0.1{leq}h/C{leq}1.25$) for the angles of attack ($0^{circ}{leq}{alpha}{leq}10^{circ}$) in the prestall regime at a Reynolds number (Re) of $2{ imes}10^6$ based on free stream velocity $U_{infty}$ and the chord length. As the physical model of this study, a cambered airfoil of NACA 4406 has been selected by a performance test for various airfoils. The maximum lift-to-drag ratio is achieved at ${alpha}=4^{circ}$ and h / C = 0.1. Under the conditions of ${alpha}=4^{circ}$ and h / C = 0.1, the effect of the Reynolds number on the aerodynamic characteristics of NACA 4406 is investigated in the range of $2{ imes}10^5{leq}Re{leq}2{ imes}10^9$. As Re increases, $C_l$ and $C_d$ augments and decreases, respectively, and the lift-to-drag ratio increases linearly.