By the use of ANSYS/LS-DYNA FEA software,numerical simulation on the cutting process of cutting plates with a reamer was carded out in the paper. The logical improvement was brought forward and the phenomenon of stress concentration was deceased by weighted analysis. The effects of different cut velocities and cutting thickness on life-spans of reamers were investigated, and the cutting parameters were optimized to satisfy the cutting precision and cutting efficiency. The study will provide a guide for the practical production.