11%。 The experimental investigations for the influencing factors of broken biennial root rate were made by a sugarcane cutter testing rig. A mathematical model was established for describing the effects of the influencing parameters on the broken biennial root rate. The effects of field factors and structure factors on the broken biennial root rate were discussed. The optimization of the broken rate under the condition of the minimum frequency and amplitude, as well as two soil bases, was performed. The results show that the frequency and amplitude have a remarkable influence on the broken biennial root rate. Under the optimal condition, the broken rate is less than 11 percent.