The invention discloses a wheel rim fixture. The wheel rim fixture comprises a base, wherein a U-shaped plate is connected into the base in a sliding fit way; a walking device for driving the U-shapedplate to slide in the base is arranged below the U-shaped plate; mounting plates are arranged on two vertical plates of the U-shaped plate; an L-shaped bracket is connected with one side of a bottomplate of the U-shaped plate in a fitting way; a stem is fixedly connected with an upright post of the L-shaped bracket through a connecting shaft; the bottom plate of the U-shaped plate is provided with a group of first through holes; a first clamping device is arranged on each first through hole; each mounting plate is provided with a group of second through holes; a second clamping device is arranged on each second through hole. The wheel rim fixture provided by the invention is simple in structure, and is convenient to operate; during the use of the wheel rim fixture, a circular plate to bewelded is pushed inwards from one end of the stem to be in sleeve joint with the outer side of the stem, so that the fixture can clamp automatically so as to be welded conveniently; a welding slag box is arranged below a welding seam, so that welding slag produced during welding can be stored effectively, and the welding slag box can be taken out for being cleaned.