The invention provides a positioning drilling tool of a pressure adjusting valve. The tool comprises a clamping base, a screw and a sliding rail; a side base and a second side base are arranged on thetwo ends of the upper of a base, and are connected with the base in a welded manner, a top sleeve is arranged at the upper end of the inner wall of the side base, and is connected with the side basein a welded manner, the screw is arranged on the rear end in the top sleeve, and the top sleeve and the screw are connected in a rotatable connection manner. The screw is arranged in the middle in a screw sleeve, and is connected with the screw sleeve in a rotatable connection manner, the screw sleeve is arranged on the upper portions of a first clamping base, a third clamping base and a fifth clamping base, and the screw sleeve is connected with the first clamping base, the third clamping base and the fifth clamping base in a welded manner. Through structural improvement, in combination withthe existing technology, the beneficial effects of being fine in structure, high in practicability and high in production efficiency are achieved, problems and shortcomings in the existing device technology are solved, and the tool has the practicability.