The three-position four-way valve, also known as the electromagnetic reversing valve, is specialized in the screw compressor unit. The three-position four-way solenoid valve belongs to the fluid working system category, and includes four cut-off portions controlled by electromagnets mounted on the valve body, which are installed on the valve body in two groups, and the electromagnets on the same side of the valve body. The power supply is connected in parallel and turned on and off at the same time; each cut-off part is composed of a compression spring, a tapered valve core, a sealing gasket, a guide sleeve, a sealing ring, a nut, and a combined sealing gasket. The valve core has a through hole, the electromagnet is opposite to the tapered valve core, and the through hole communicates with the front cavity and the rear cavity; the front cavity of the cut-off portion 15 and the front cavity of the cut-off portion 9 share the A port, and the cut-off portion 15 The middle cavity passes through the D port, the middle cavity of the cut-off portion 9 passes through the C port, the middle cavity of the cut-off portion 14 and the middle cavity of the cut-off portion 11 share the B port, and the middle cavity of the cut-off portion 15 communicates with the front cavity of the cut-off portion 11 The middle cavity of the cut-off portion 9 communicates with the front cavity of the cut-off portion 14. The utility model has the advantages that it has no internal leakage problem, prolongs the service life, and is not restricted by pressure, and is suitable for gas and liquid control.