Abstract: Abstract: The cutting system is the key component of small whole-stalk sugarcane harvester and it is located in front of the machine. Whether it can convey the sugarcane smoothly into the next process or not after cutting is directly related to the working performance of the machine. Currently the main problems of the original prototype include serious blocking, lower cutting quality, less efficiency and higher impurity during harvesting, which seriously hinder the application of the harvester. In order to improve cutting quality and to reduce the sugar stalks loss under the premise of low stool damage rate, some technical improvements were taken. The cutting device, layout and lifting way of the cutting system of the original machine were modified, and an aggressive knock-down roller was added in frond of the cutting system.Screw mechanism with rubber was added to the base-cutter. It can enhance the friction coefficient between sugarcane and transport mechanism, which is helpful for sugarcane entering the feeding roller. Theoretical analysis indicated that the amplitude of the blades was lower if the cutting system was located in middle of the machine than that in frond of the machine. So the cutting system was moved from ahead to middle of the wheels. The original lifting way of the cutting system was vertical, it is not fit for high plots, so it was replaced by revolving round its back-end. By installing an aggressive knock-down roller in frond of the cutting system, it can improve the feeding speed of sugarcane and reduce the amount of overlap sugarcane. The modified prototype was made based on the technical improvement and vibration test was studied. Experiment results showed that the amplitude of the blades was smaller, the stool damage rate was lower. Contrast tests were carried out in the field and the results showed that the new cutting system can improve the feeding ability and decrease the probability of blockage during harvesting. The best cutting quality could be obtained under the condition that the speed of feeding roller was 200 r/min, the speed of crop lifter was 120 r/min, the speed of base-cutter was 650 r/min and speed of cleaning roller was 770 r/min,. After improvement, the stool damage rate reduced from 15.9% to 4.7%, non-damage rate of the base of sugarcane stalks enhanced from 51.0% to 82.5%, the trash content decreased from 5.12% to 2.86%, the production efficiency raised from 1.129 to 1.894 kg/s, and it could meet the sugar-refinery requirements for sugarcane. The research can provide a reference for the mechanical design of the whole stalk sugarcane harvester.