The generation process of the morphology of root system in plants was simulated on the basis of studying the growth mechanism of natural root system.The axiom of uniform stress was used to control the growth process of root system.According to the generation mechanism of root system,a new design methodology of structural topology optimization was suggested.The results show that the shear stress between the soil and roots is the primary mechanical factor to control the morphology of root system.The structural topology optimization design method mentioned above can be applied to the layout design of stiffeners on thin-wall plate and shell structures.By use of the method,the approxi- mate optimum topology model of the structure can be established quickly and be used to the succeeding detail design in structural design process.