The invention discloses a motion camera accessory supporting 4K picture quality shooting, which comprises a motion camera body, the motion camera body comprises first connecting pieces and first inserting pieces, the front side and the rear side of the motion camera body are symmetrically provided with the first connecting pieces, and the first inserting pieces are inserted into the first connecting pieces; auxiliary mechanisms are arranged outside the front side and the rear side of the first inserting piece, a heat dissipation mechanism is arranged on the right side of the motion camera body, a user can clamp the outer ends of two right-angle fixing clamps to a rearview mirror fixing shaft of an automobile, and when the two right-angle fixing clamps get close, clamping and fixing can be automatically completed under the magnetic attraction effect; at the moment, through the arranged auxiliary mechanism, the head-mounted use effect can be achieved, meanwhile, the auxiliary mechanism can be taken down to be used as a vehicle-mounted automobile data recorder, so that the convenience of the camera is improved on the whole, meanwhile, the functionality of the motion camera body after being used in cooperation with the auxiliary mechanism is enhanced, and the use effect of a user is greatly improved.