The deformation of the thinwall cylinder parts affected by different clamping force and cutting force in turning was analyzed with finite element method based on Pro/EngineerMechanica software. By contrasting the simulation results with different clamping ways and cutting parameters, the technological scheme was optimized. The cutting test results show that the stimulation data and actual measurement data are better consistent. So this kind of analysis method can be used as an effective means in quantitative analysis to work out the technological scheme for thinwall cylinder parts processing. It changes traditional method of establishing clamping ways and cutting parameters through experience or cutting tests.