Improving the cutting performance, especially the cutting quality of sugarcane harvesters is the most magnificent problem for popularizing the application of the havesters. Much research has been done on most effect factors but rare on the influence of rigidity enhancement of sugarcane cutter. Indeed, the rigidity of sugarcane cutter has notable influence on the quality of sugarcane cutting，as it effects its vibration and the vibration in turn brings great damage to the cutting quality. This paper analyzes how the rigidity of sugarcane cutter effects its working vibration by building up its mathematical model, then further investigates it by making a dynamical simulation analysis to compare two cutter structures with different rigidity based on ANSYS and ADAMS, and validate the actual effect of enhancing the cutter rigidity through a physical experiment. The result shows enhancing the rigidity of the cutter could lead to notable improvement of sugarcane cutting quality.