In this paper, the influence of a plastic straw cutting machine on product quality is analyzed, and the overall scheme of optimal design of traction device of cutting machine was proposed, and the main parts of the optimized traction device are designed. Three-dimensional models of main parts are established for finite element analysis, and the simulation results show that the optimized parts fully meet the equipment requirements. Optimized traction device of cutting machine is assembled and prototype experiment. The experiment results show that: After optimization, the difference between the vertical and horizontal values of the straw is obviously reduced and the qualified rate of roundness of the straw is improved from 10% to 100%.;The length of the straw tends to a constant value, and the qualified rate of straw length is improved from 80% to 100%.So the optimal design of the traction device of the cutting machine improves the roundness and length control of the straw in the production process, improves the product qualification rate, and provides theoretical experience for the subsequent optimization of the device.