Most thin-walled structures tend to be failure with their instability under pressure load.To be reinforced with stiffeners is an effective way to improve the bucking bearing capacity of thin-walled structures.In this paper, ANSYS APDL is used to set up the parameterized model of thin-walled stiffened cylindrical shell.Linear buckling analysis under axial compression of thin-walled stiffened cylindrical shells which have specified volume and different number of stiffeners is carried out.The results show that the number of stiffener, the skin thickness and the section sizes of stiffener all have important influence on the structures bucking bearing capacity.The optimization model of thin-walled stiffened shell which has a specified volume is developed and solved by genetic algorithms.The objective function of the optimization model is the maximum buckling bearing capacity.Its design variables include the number of longitudinal stiffener, the skin thickness and the section sizes of stiffener.The structural parameterized analysis process is set up by ANSYS APDL and the automatic re-analysis of the structure is realized.MATLAB genetic algorithms toolbox is applied in the solution process at the same time.Through this optimization program, the longitudinal stiffeners number, the skin thickness and the section sizes of stiffener can be solved out.Comparing with the non-optimized structure, optimized structure has a significant improvement on linear buckling bearing capacity.When overall buckling and local buckling occur at the same time, as same as the optimized structure, thin-walled stiffened cylindrical shell would gain the maximum bearing capacity.Finally, nonlinear buckling analyses of stiffened cylindrical shell which is subjected to axial pressure with initial geometric imperfections are studied.The analyses are considered with geometric nonlinear and material nonlinear.Compared with linear buckling analyses, optimal solution with linear buckling analyses is not the maximum buckling load value of structure.The reason is that when there are fewer stiffeners, linear buckling bearing capacity could be much smaller than the maximum bearing capacity of the whole structure.Otherwise, when there are more stiffeners, linear buckling bearing capacity could be larger than the maximum carrying capacity of the whole structure.When structures volume, diameter, height and the section sizes of stiffener are all fixed, stiffeners number must be selected within an optimum range to get the maximum bearing capacity of thin-walled stiffened cylindrical shell.Reinforce either more stiffeners or fewer stiffeners cannot improve the buckling bearing capacity of stiffened cylindrical shell.When there are too few stiffeners, structure which is under axial compression would occur local buckling prematurely.That will be harm to the structures bearing capacity.When there are too many stiffeners, the thin-walled stiffened cylindrical shell would be sensitive to initial geometric imperfections.Only when suitable number of stiffener is adopted, the maximum buckling bearing capacity of structure would be obtained.