Abstract: Existing base cutter in sugarcane harvester has obvious problem that maximum soil-intrusion position was inconsistent with root cutting position，which caused increased both in power dissipation and impurities rate（high content of mixed soil）.In view of this problem，a base cutter with inward-leaning angle was developed.With dish rotating speed and inward-leaning angle as influencing factors，root rupture rate and impurities rate as experimental indexes，quadratic orthogonal rotation center combination experiments were carried out and response surface models of performance indexes and working parameters were obtained.Experimental results showed that inward-leaning angle had a greater influence on impurities rate，and dish rotating speed had obvious significance on both indexes.Optimal combination of working parameters was obtained by multi-objective optimization with dish rotating speed of 269 r/min and inward-leaning angle of 16.4°.Expected results of root rupture rate and impurities rate were 9.45% and 6.61% respectively，and verification experimental results were 9.66% and 6.88%.Comparison test showed that base cutter with inward-leaning angle got 10.6% reduction in impurities rate compared to original models with a prerequisite of a better root rupture rate.