The disc saw cutter system is one of the key components in caragana korshinskii harvester, and determines the cutting quality of caragana korshinskii. We established a simplified model of the cutter based on the parameters of each part of the disc saw cutter system, and built the cutting object caragana korshinskii model combining with the caragana korshinskii parameters. These parameters were introduced into dynamic analysis software ADAMS, and the cutting object was replaced as flexible body. The rigid-flexible coupling dynamic analysis of caragana korshinskii was conducted while the cutting institution was working. Considering the diameter, thickness and rotational speed of the disc saws as factors, the impact-force of x (direction of operation), y (vertical upward), and z (horizontal to left direction) axes between caragana plant and cutter were selected as the response function to represent the caragana cutting efficiency. A virtual orthogonal test of three factors and three levels was performed on parameters, which were related to the cutting efficiency and power. The response surface regression equation of each indicator was obtained, and the validation and comparative analysis was performed by field experiment. The result showed when the disc saw diameter was 400 mm, thickness was 5mm and the rotational speed was 1500r/min, the cutting power of one cutting component was 12.32kW, and the cutting efficiency was the best. This study provided the design basis for selecting the parameters of caragana korshinskii combine harvester.