The mechanical strength of rear end of sugarcane stalk is significant lower than the middle and basal part. A tail-breaking mechanism was designed. When the sugarcane stalk passing through this kind of mechanism, the tails and 5-6 pieces of young leaves could be broken. Its working principle was analyzed, and the orthogonal experiments were conducted to study the influence between the following four factors: rotate speed of feeding and output rollers, rotate speed of tail-breaking rollers, the center distance between the top and bottom tail-breaking rollers, and the relative installation position angle of the top and bottom tail-breaking roller's elastic components. The result shows that the optimal parameters were as following: rotate speed of feeding and output rollers of 250 r/min, rotate speed of tail-breaking rollers of 550 r/min, the center distance between the top and bottom tail-breaking rollers of 300 mm, and the relative installation position angle of the top and bottom tail-breaking roller's elastic components of -20°. The best tail-broken rate in 4-6 sections below the growth point of cane stalk reached to 63.3%. The average length of these tails was 212 mm and standard deviation was 57 mm which meet the agronomic requirements.