Abstract: The genetic/sensitivity-based hybrid algorithm was used for the design studies of aeroelastic tailoring of a forward-swept composite airplane. The design objective is to minimize the weight of skin. The ply-thicknesses of wing skin were selected as design variables. The constraints were strength, displacement, lifting efficiency, aileron efficiency, divergence speed and flutter speed. The studies demonstrate that it is difficult to meet design requirements in preliminary design of aircraft structure when sensitivity-based algorithm is used along. The genetic/sensitivity-based hybrid algorithm could outperform sensitivity-based algorithm operating alone. The hybrid algorithm is suitable for preliminary design of aircraft structure. The effect of ply-orientation on optimized weight while satisfying the above multiple constraints was discussed. The results indicate that the optimized weight of the forward-swept composite wing is relatively insensitive to ply-orientation of skin when skin lay-up consists of 0°, 90° and ±45° fiber directions and wing is subjected to multiple constraints on static constraints, static aeroelastic constraints.