Abstract: In order to verify the throttling effect of the vortex tube, a physical model is established, and methane is used as the working fluid. The variation rule of physical parameters in the flow field is simulated based on Fluent. The analysis shows that when the cold flow rate is 0.5, methane (298 K, 12 MPa) rotates in the vortex tube at a high speed. The external swirling gas temperature rises to 303 K, closing the tube wall to the hot end outlet. The internal swirling gas temperature decreases to 293 K, around the axis to the cold end outlet. Externally swirling high temperature gas wrapped in internally swirling low temperature gas flow can effectively alleviate the crystallization of pipe wall and avoid gas freezing blockage; the axial position produces pressure stagnation point and velocity direction break point, along the flow direction, the internal and external swirling gas have energy loss, resulting in pressure and velocity decrease. The throttling interval is about 3 MPa, and heat transfer loss is ignored. After the vortex tube confluence, the temperature drop interval of the gas is almost 0 K, while the temperature drop interval of the throttle valve is 9.8 K. The comparison of throttling and depressurization process flow with throttle valve and vortex tube as key equipment shows that the energy separation effect of vortex tube is better than that of throttle valve, which not only reduces the temperature drop range of the gas, but also has a significant throttling effect. In practical application, the throttling process of the gas transmission station can be simplified, and the investment and operation costs can be reduced.