The solar powered aircraft ribs are light, thin structure of large number. Proper rib structural layouts are important to the aircraft lightening and the wing stiffness etc. Based on the rib structures of some typical solar powered aircraft, a topology optimization design method of the ribs were introduced: Firstly, a typical solar powered aircraft rib structure was optimized, based on the Bi-directional Evolutionary Structural Optimization(BESO); Secondly, the specific designs of the rib structure were given; Lastly, the structural strength, stiffness and stability of the rib were verified through Finite Element Method. Though the method in this paper, a more suitable structural layouts of the solar powered aircraft ribs was obtained.