Aiming at the low chassis of the conventional cutter-sunner, the lateral spreading structure of the vertical cutting table leads to the difficulties in side-row harvest, the poor quality of cutter-sunner spreading, and the poor pass-through performance of the machine and other problems. The design of a high ground clearance suspended cutter-sun machine, the use of the middle laying form, the transmission system using hydraulic motor drive. The whole machine structure is mainly composed of a frame, transmission device, suspension device, reciprocating cutter, screw conveyor roller, grain separator and hydraulic system. Kinematics, dynamics and finite simulation analysis were conducted for the suspension mechanism of the sun cutter, and the results show that the designed suspension structure can meet the requirements in field operation. Taking the coefficient of variation of spreading width and the coefficient of spreading uniformity as the indexes, the forward speed of the unit and the rotational speed of the main drive shaft as the influencing factors, orthogonal tests were conducted, and through the establishment of the regression equation model, the optimal working state of the cutter-sunburner was acheived obtained when the forward speed of the unit was 1.028m/s and the rotational speed of the main drive shaft was 430.042r/min. After several tests, the coefficient of variation of spreading width is 5.897% on average, and the coefficient of spreading uniformity is 104.251% on average. The results show that the cutter-sun dryer can complete the cutting and laying operation at one time under normal working condition, with neat stubble cutting, smooth conveying and orderly laying, which can meet the requirements of subsequent drying , picking and threshing operations.