Abstract: A model of structure optimization is established as an example of study on ring-stiffened cylindrical shell by using iSIGHT. The core functions of this software are introduced. In the system of multidisciplinary design optimization (MDO) ,Patran/Nastran is integrated to carry out optimization design of ring-stiffened structure. By this combined methods, the optimizations of the structure are conducted both to the normal modes and the acceleration of frequency response.