The performance simulation of a small-scale corn harvester’s divider and snapping roll for hilly area was analyzed by using ADAMS. A 3-D model of the corn harvester header was established with Pro/E. The preprocessed model was imported into the ADAMS environment to build the virtual prototype model. A performance simulation of divider and snapping roll was done. The results showed that the design of the divider shape had some defects, which lead to the result that the cornstalks cannot be normally fed. Meanwhile, it gave the best values of speed and inclination of the snapping rolls, the optimal parameters were: snapping roll speed of 800~1000r/min, and snapping roll inclination of 30°.