Based on detail analyzed an optimization model of rotor dynamics of aeroengine multi-rotors system, the sum of weight of normal subjection function of fuzzy sets theory was used to describe the distribution of multi-order critical rotor speeds versus multi in common used operating speeds, and to formulate an optimal objective function. According to the design specification and criterion, design variables and constraints which markedly influence the critical rotor speeds were chosen. Finally, an optimization mathematics model for rotor dynamics of aeroengines was formulated successfully. The integrated tool of aeroengine rotor dynamics was set up with VC+ +6.0, where Windows' I/O interface and visual post processing were implemented. The optimization algorithm was encapsulated to the form of DLL, MSC/PATRAN/NASTRAN was also integrated in it to optimize and analyze the deformation and stress for the rotor dynamics of aeroengine multi-rotors. Multi-rotors of an aeroengine were optimized and analyzed with this tool to examine its validity.