Based on the finite element, a method based on full stress rule is proposed for the thickness optimization of wing skin. Firstly based on full s tress rule, the thickness of each element is updated. Then in order to meet t he requirement of continuity, the thickness of each element is modified by weigh ted average method. After performing the weighted average method, an overall modific ation is implemented for skin thickness distribution to ensure that all elements satisfies the stress constraints. This method is applicable to problems involvi ng w ith metal skin and composite skin. Finally, numerical examples demonstrate the f easibility and effectiveness of the proposed method.