Abstract: Both mathematical and parameterized FEM (Finite Element Method) optimization models for an orthogonal rib-stiffened thin cylindrical shell under axial loading were established, and the calculations were done using Ansys software package. In addition to the effects of the loads and yielding limits of materials upon the optimization design, the effects of structural parameters upon the buckling loads and modes were also discussed. An optimization design method based on parameterized FEM analysis was developed accordingly; sample optimization design using this method was compared with calculations of the previous mathematical method. The mathematical model possesses legible physics sense as far as the design of rib-stiffened thin cylindrical shell is concerned. Results obtained through the two methods show satisfying accordance, further, the latter method based on FEM models possesses better adaptivity and can be utilized conveniently with Ansys software package.