The invention discloses a special machine tool for drilling, expanding and reaming, and relates to the technical field of a cold processing device. The special machine tool for drilling, expanding andreaming comprises a workbench with a lead rail and a control box; a slide base is arranged on the lead rail, and the slide base is provided with a positioning mandrel and a positioning pin for positioning the work piece; a cover plate and a nut are sleeved on the positioning mandrel for fixing the work piece; the left side of the lead rail is provided with a drilling device and an expanding device, and the right side thereof is provided with a reaming mechanism; the boring device and the reaming device are connected with the control box, the middle part of the lead rail is provided with a limiting hole, and the slide base is provided with a positioning pillar matched with the limiting hole for limiting the slide base, so as to control the work piece position and guarantee the location degree of drilling, expanding and reaming. After the work piece is positioned and fastened on the slide base, the slide base is orderly moved to the drilling, expanding and reaming positions; after beingpositioned by the positioning pillar, the work piece is performed with drilling, expanding and reaming by means of a drilling device, an expanding device and a reaming mechanism, thus the processingprecision of an axial hole on a driver box is guaranteed, and three stations of drilling, expanding and reaming are integrated, the working efficiency is improved.