Abstract: Due to complicated configuration and multi control surfaces, the flutter characteristic design of T-tail is complicated and there are many parameters in the process of establishing dynamics finite element model, so the designers face more difficulties. In order to solve these problems , optimization methods was introduced into design process. According to the virtues of genetic algorithm and sensitivity algorithm, the two methods are mixed for natural vibration optimization and ordinal applied for flutter optimization respectively. The sensitivity formulas about natural frequency and flutter damp to structure parameters were discussed, and the math models about optimization design were established. With the methods using for structural dynamics optimization of a real T-tail model, not only the time of designing has been reduced to a great extent, but also the design precision has been assured, with the error of natural frequency below 3%. The flutter speed increased with the mass of structure minimized, and the result provides references in practical structural design.