The invention discloses a maintenance-free collision system for an ore hopper car unloading mechanism. The upper portion of a door leaf is hinged to a compartment, a rotary shaft is arranged on the bottom of the compartment, a pull rod is arranged on the rotary shaft which is hinged to the lower portion of the door leaf through a connecting rod, opening and closing of the door leaf are achieved under the forward and reverse rotation of the rotary shaft, the rotation of the rotary shaft is achieved by colliding with a corresponding door opening collision block and a corresponding door closing collision block which are arranged on the ground in advance during engine operation, so that unmanned operation is achieved; furthermore, the heights of the door opening collision block and the door closing collision block are constant, and the maintenance-free effect is realized without adjustment; besides, safety and reliability are realized, time and labor are saved, and door opening and closing efficiency is quite high.