The purpose of this paper was to validate the effects of airfoil thickness ratio on the characteristics of a family of airfoils. Re-search was carried out in different ways. First, tests were conducted in the wind tunnel. And numerical simulation was performed on basis of tests. Results from calculation were consistent with tests, indicating that numerical method could help evaluate characteristics of airfoils. Then the results were confirmed by compared with empirical data. The study also showed that the determinant of lift was not the thickness ratio, but the angle of attack, the relative camber and the camber line. The thickness ratio appeared to have little effect on lift coefficient at zero angle of attack, since the angle of zero lift was largely determined by the airfoil camber. According to the research, numerical simulation can be used to determine the aerodynamic characteristics of airfoils in different environment such as in the dusty or humid air.