In the traditional iterative design process for composite structures, it is difficult to achieve an optimal solution even though a great effort is made. A genetic optimization system based on grid technology offers an automatic and efficient approach for composite structure redesign and optimization. A genetic algorithm system, which integrates Genetic Algorithm Optimization (GAO) software and a Finite Element Analysis (FEA) based commercial package, has been developed as a tool for composite structure design and analysis. The GAO is capable of tailoring large number of composite design variables and taking the time-consuming FEA results to calculate objective function value and conduct optimization in high accuracy. By operating the system employing the Grid technology and Artificial Neural Network (ANN) method, significant time saving in numerical analysis can be achieved. A user friendly interface has also been built in the system. In the paper, aeroelastic tailoring of a composite wing has been taken as a numerical example to demonstrate the optimization approach. The numerical results show that an optimal design has been achieved to meet the design requirement.