The utility model relates to a small diameter tube probe wedge outer arc grinding device matched with a special small diameter tube test block, and belongs to a small diameter tube probe wedge outer arc grinding device in ultrasonic inspection. A magnetic body is connected in a base with an opening in the side face by threads; a sliding rod sleeve seat is fixedly connected with the upside of the base; a sliding rod sleeve is connected with the sliding rod sleeve seat in a rotating way; a sliding rod is connected with the sliding rod sleeve in a sliding way; the special small diameter tube test block is connected with the base by magnetic force; the axle wire of the sliding rod which slides in the sliding rod sleeve and the axle wire of the special small diameter tube test block are located on the same plane; a small diameter tube probe wedge clamping seat is hinged to the sliding rod; a small diameter tube probe wedge is fixedly connected with the small diameter tube probe wedge clamping seat by an adjusting shim and a locking screw. The small diameter tube probe wedge outer arc grinding device matched with the special small diameter tube test block has the advantages that the structure is novel, the grinding precision is ensured, the grinding effect of the small diameter tube probe wedge on the special small diameter tube test block is improved, and the percent of pass is improved.