According to the features of roadheader support legs, including special shape, big size and high machining precision etc, a special boring fixture for roadheader support legs was designed after analyzing the boring process of the part. It included fixture apparatus, plane support clamping device, inclined plane aided support clamping device, side positioning device and tail positioning device. Not only the precision and efficiency of boring are improved, but also certain reference value is provided to the forming of similar parts.