The invention discloses a collision grinding type ultrafine smashing device. The device mainly comprises a feeding device, a collision device, a grinding device and a discharging device, wherein a feeding barrel body in the feeding device is matched with a material collecting disc; the material collecting disc is mounted on a main shaft through a key; discharge holes are formed in the edge of the material collecting disc; the main shaft rotates to drive the material collecting disc to rotate; material leakage pipes in the collision device are in threaded connection with the discharge holes of the material collecting disc; when materials are accelerated, the materials are thrown through a pipeline under the action of centrifugal force at a high speed to collide with collision pieces to be crushed; the grinding device comprises three levels of grinding mechanisms; the materials are sequentially fed into the first-level, the second-level and the third-level grinding mechanisms under the action of gravity; and grinding mechanisms comprise grinding discs and grinding blocks. According to the collision grinding type ultrafine smashing device, materials of which the particle size difference is relatively large can be smashed at a time, the condition that a pulverizer needs a sieving net is improved, the smashing efficiency and the smashing effect are improved, and the production efficiency for producing ultrafine powder can be improved.