Abstarct: Achieving the maximum efficiency with the minimum cost through selection of an effective system is of engineering arts. This need was the motive to creat and develops the science of optimization. Finding the topology, or the pattern of joints and members, is among the most interesting topics in structural optimization. Genetic Algorithm (GA) is proved to be an efficient method of optimization. The slow progress in optimization process, lake of information on the parameters and the governing rules in GA such as the number of generations, rate of cross over, rate of mutation, and the selection process causes the selection of local optimum point and termination of GA process. In the present research a new method is proposed to find the optimum topology and cross section for truss elements by enhancement of the GA. In this regard, a complete system including several subdivisions, called islands, is assigned to search the design domain. In order to form the islands, the well-known GA techniques were chosen and examined and those with the best result were selected to be used in each individual island. In the other word, the GA techniques recommended in the literature were used in the islands to reduce the effects of GA while the quality of the results was improved.