A rapeseed circular chain cutter was designed to solve the problem of large inertia and the header vibrating for the traditional reciprocating cutter. The cutter is mainly composed of a dynamic bending knife with involute shape, an upper and a lower fixed knife, a power and a transmission. An intermediate moving bending knife cooperates with the upper and lower fixed knife to realize a one-way circulating cutting with double supporting. Combined with the self-made cutting test bench, the effects of cutting speed and cutting height on the cutting force and the cutting power are tested. The results show that the cutting force and the cutting power decrease with an increase in the cutting speed. The dependence of the cutting force on the cutting height fit the equation of y=–0.058 8x+158.17. The fitting equation of the cutting power dependent on the cutting height is y=–0.085 9 x+308.98. The field cutting test shows that the stalks are neatly cut without missing cutting, knife blocking, and stalk pulling, when the cutting speed is 2 m/s and the height is 400 mm from the ground.