The invention provides an air pressure regulator. The air pressure regulator comprises a mask and an air pressure regulating pump, wherein the air pressure regulating pump is communicated with the mask through a duct in a sealed manner; an air inlet and an air outlet are formed in the air pressure regulating pump; the air inlet is located in a position where the air pressure regulating pump is communicated with the duct; the air pressure regulating pump reduces pressure of the air in the air pressure regulating pump, so that the air in the mask and the duct is sucked into the air pressure regulating pump via the air inlet and discharged via the air outlet. The air pressure regulator can set various parameters of a high-altitude training environment automatically, performs flexible regulation according to persons having different training requirements, simulate a real high-altitude air environment, strictly control training requirement standards and meet training requirements of regular and gradual improvement.