Abstract: A gas pressure regulating device is provided which comprises a housing, in which a first mounting cavity for installing a level-1 depressurization mechanism and a second mounting cavity for installing a level-2 depressurization mechanism are provided in sequence along the air intake direction; the level-1 depressurization mechanism comprises a sliding sleeve, and a mounting tubing which is communicated with the gas inlet is formed inside the first mounting cavity, and the sliding sleeve is slidably assembled between an outer wall of the mounting tubing and an inner wall of the first mounting cavity; the other end of the sliding sleeve is provided with a gas discharge orifice and a sealing gasket, and the gas inlet connector is in communication with the first mounting cavity through the gas discharge orifice; the sliding sleeve slides along the axial direction to adjust the openness of the gas outlet to realize the level-1 depressurization.