Abstract: A minimum weight design on a composite aircraft wing structure subjected to displacements and size constraints conducted in this paper,The ply-thicknesses of composite skin are stimulated by polynomials.The Finite element method is ussd in the structural analysis.A feasible direction approach is applied to the optimum proc0dures.The coefficients of polynomials and the thicknesses or sectional are,as of finite elements are taken as design variables,By grouping the variables,the scale of the problem is deduced,Examples of a composite material box sector and a composite material wing strure show satisfactory results.