Abstract: The “ice blockage” purge device is an important compoent for replacing the test equipment and realizing nitrogen supply to the equipment.In order to verify the rationality of the design and explore the characteristics of its internal fow field, this paper first establishes a three-dimensional model of the purge device,and then conducts a simulation analysis of the changes in the velocity field and pressure field of the purge device under different opening degress. The research results show that: as the valve opening increases, the maximum velocity at the valve flap gradually decreases; the gas flow pattern is laminar when it enters the purge device, but after passing through the valve flap, it flows in a spiral shape towards the outet, which can better blow away the impurities in the gas pipe. The simulation of the internal flow field of the purge device in this paper can point out the direction for the optimization of thi structure, and provide data support and theoretical basis for improving the equipment support efficiency.