In order to improve the quality and efficiency of civil aircraft conceptual/preliminary design, the implementation of wing structure and associated fuel tank design in a computer aided aircraft conceptual/preliminary design system were studied. The coordinate of wing-like components was defined. The parametric modes of wing, spar, stringer, rib and skin were represented. A prototype system for wing structure and associated fuel tank design were constructed, the characteristics such as weight, center of gravity, inertia were estimated too. The automatic adjustment and estimation of geometrical properties for wing structure and fuel tank were implemented, which were the base of multidisciplinary design optimization that took into account weight, aerodynamic and structure. At last, an instance was given to illustrate that the methods of wing structure design and automated adjustment are effective.