Abstract: The optimization design of composite strut-braced wings with aeroelastic constraint was conducted by using the genetic-gradient hybrid algorithm, and a comparison between the strut-braced wing configuration and conventional configuration was also presented. The objective was to minimize the structural mass subject to the constraints of deformation at wingtip, buckling and flutter speed. The composite layups and structural parameters of strut were designed in the case of critical load conditions. The influences of strut locations on optimal designs were investigated. The results indicate that the material in the bending direction can be dramatically reduced by using the composite strut-braced wing, which has an obvious advantage in reducing structural mass. The structural mass, buckling and distribution of torsion stiffness can be significantly affected by the strut location. The buckling failure of strut should be taken into account in the structural design of composite strut-braced wing.