The invention discloses an abrasion-resistant tungsten steel milling cutter of a numerical control key cutting machine and a using method. The tungsten steel milling cutter comprises a tungsten steelmilling cutter head, fine pores, a cutter bar, an adapter pipe, a column groove, an internal thread pipe, a guide pipe, bearings, an annular groove, strip holes, rectangular grooves, return springs, clamping blocks and fixing blocks. According to the tungsten steel milling cutter, the design is reasonable; by rotating the internal thread pipe to the outer side of the cutter bar, the inner side ends of the four clamping blocks can gradually extend into the column groove to be pressed against a cutter driving connecting shaft bar, and thus, the effect of firm connection between the cutter and adriving shaft is achieved. The bottoms of the clamping blocks are sprung into the strip holes by separation of the internal thread pipe from top ports of the strip holes, under the action of the return springs, so that the clamping blocks have the springback function on clamping and fixing structures. A cooling liquid is injected into a space formed by an annular groove and the adapter pipe, and finally sprayed around the tungsten steel milling cutter head via the fine pores, thereby being capable of making full contact with the high-temperature metal turning surface.