Positioning device for valve machining

The utility model relates to the technical field of valves, in particular to a positioning device for valve machining, which comprises a bottom plate, supporting seats and a screw rod, the supporting seats are fixedly arranged on the periphery of the lower surface of the bottom plate, two sliding bases are movably arranged on the upper surface of the bottom plate, and the screw rod is arranged on the bottom plate. The two sliding bases are both connected with the upper surface of the bottom plate in a sliding mode, first connecting rods are fixedly arranged on the upper surfaces of the two sliding bases, and second connecting rods are arranged at the upper ends of the two first connecting rods. In this way, different positioning mechanisms can be selected according to the shape of a valve during use, the overall selectivity of the device is more, a second motor can drive a second positioning mechanism to overall turn over, in this way, when different faces of the valve are machined, repeated disassembly and r