The invention relates to an upper ejector rod type corncob breaking-off acceleration mechanism and belongs to the technical field of agricultural machines. The mechanism comprises a swing type corncob breaking-off hand (1), a hinge shaft (2), a top plate (3), a fixed rail (4), a guide column (5) and a triggering rod (6). The mechanism is characterized in that the mechanism is fixed to a wing panel of a driving device simulating manual corncob breaking-off to achieve corncob breaking-off acceleration; the guide column (5) is fixedly connected with the triggering rod (6) and the top plate (3), the top plate (3) is located above the guide column (5), and the guide column (5) moves upwards along the fixed rail (4); the swing type corncob breaking-off hand (1) is installed on a corncob picking mechanism through the hinge shaft (2) and located above the top plate (3) and can rotate around the hinge shaft (2), the top plate (3) moves upwards, and the swing type corncob breaking-off hand (1) is pushed to rotate around the hinge shaft (2), and accordingly corncob breaking-off acceleration is achieved. The mechanism is good in bionic effect and small in power consumption, reduces energy consumption, saves energy, meets the requirement for environment friendliness, and is easier to popularize.