Abstract: A kind of Cyperus bean harvester was designed, which was mainly composed of frame, conveying and separating device, threshing and separating device, cleaning device and other components．The multiple cleaning functions made harvester had good fluidity and separation, and could realize efficient separation and cleaning of seeds, impurities and roots in mechanized harvesting process of Cyperus soybean．Taking grain loss rate and impurity content rate as evaluation indexes, optimum parameter combination of Cyperus bean harvester was finally determined by setting different rotating speeds of each part and conducting three factor and three level orthogonal tests, which provided a basis for design, improvement and parameter selection of key components．