Recently, hypermarkets grow up rapidly in Taiwan. However, most layouts of these hypermarkets are planned empirically. The hypermarket managers in Japan developed a conceptual theory, called “magnetic theory”. The goal this theory is to guide consumers into the hypermarket and put the goods in the proper place where they can attract the consumers’ attention. We proposed a layout model, which was constructed by facility layout planning under magnetic theory. This study utilized both relationship and normalized flow between departments to evaluate hypermarket layout. We utilized genetic algorithm procedure complied with. Taguchi method was to find the best design parameters. The results of this study can provide the hypermarket managers good advices during the planning of hypermarket layout.