The invention provides a boring blade for machining a conduit hole. The longitudinal section of the boring blade is a right-angled trapezoid; the lower bottom surface of a boring blade body is welded with a cutting part of which the longitudinal section is a right-angled trapezoid in a butt way via a welding flux; the middle of the bottom surface of the cutting part is provided with a rectangularlocation groove; the bottom of the location groove has a slope structure, and the section of the bottom of the location groove adjacent to the cutting part has a structure that an acute angle side isinclined inwards; the cutting part has an integrated structure and is made of polycrystalline diamonds; and the location groove is machined by laser. By the invention, the machining surface roughnessand the machining precision of the blade are improved, the product quality is greatly improved, the service life of the boring blade is prolonged, and the cost is effectively reduced.