When planted in one year two crop area of China, it is important to reduce energy consumption and improve planting performance, and ensure the anti-blocking performance as well. When the support cutting was carried out, the cutting force needed became smaller because some of it was got from external force. Taking support cutting device—floated support anti-blocking device as research object, the static strength finite element analysis of key components blade and support plate was conducted with ANSYS software. The load of blade came from resistance of cutting straw and soil, and the load of support plate came from holding power of straw and soil. On the basis of established finite element model, a series of stress figures were obtained after calculation. The result indicated that the stress of blade mainly focused on x>0 area of right hole heart, and the area from hole heart to turning place. The maximum of equivalent stress was 2151.2Pa. The stress of support plate mainly focused on arc plate area and flat plate area closed to the arc plate side. The maximum of equivalent stress was 3.77×105Pa. The field experiment showed that the machine had a good working performance and deformation was not found on the blade and support plate.