When air passes through the wing of an aircraft, lift and drag will be produced due to the pressure difference between the upper surface and lower surface. Lift-to-drag ratio, an important term that shows the aerodynamic efficiency, mainly depends on the shape of the airfoil. To increase the lift-to-drag ratio, it is necessary to optimize the airfoil by changing its camber, camber location or the thickness. Javafoil and Ansys Fluent are used to do the modeling and analysis processes to find the maximum value of the lift-to-drag ratio of an NACA airfoil at certain angle of attack for low Reynolds Number flow. By converge the results, we can see the effects of these essential parameters on the performance of an airfoil, which may contribute to the further wing design optimization.