The subject of this study is Lycomig -IO - 360 reciprocating aeroengine, the torsional vibration calculation model of crankshaft system is established, calculated the torsional vibration characteristics. The torsional vibration response of crankshaft system are analyzed base on two work conditions, which are different rotation speeds with equal inlet pressure and propeller pitching. The research results show that the higher rotation speed with equal inlet pressure, the stronger torsional vibration of crankshaft system, high rotation speed with low inlet pressure will significantly enhance the torsional vibration; Propeller pitching with equal rotation speed will change the torsional vibration of crankshaft system, the larger pitch, the stronger torsional vibration.