The invention discloses a gas pressure reducing valve. The gas pressure reducing valve comprises a lower valve cover and an upper valve cover, wherein the upper valve cover and the lower valve cover are hermetically and fixedly connected; the upper valve cover and the lower valve cover are each internally fixedly connected with a rubber film; the upper valve cover and the lower valve cover are each internally divided into an upper gas chamber and a pressure reducing chamber by the corresponding rubber film; the lower valve cover is provided with a gas inlet and a gas outlet which communicate with the corresponding pressure reducing chamber; the lower valve cover is provided with a gas charging opening for the gas inlet to communicate with the corresponding pressure reducing chamber; a regulating spring is fixedly connected between the upper valve cover and the corresponding rubber film; one surface, far away from the regulating spring, of the corresponding rubber film is connected witha lever; the lever is rotationally connected with the inner wall of the lower valve cover; the end face of one end, positioned inside the pressure reducing chamber, of the gas charging opening is a sealing plane; the lower valve cover is rotationally connected with a cover plate; the rotating center axis of the cover plate is parallel to the sealing plane; the lever is positioned between the lever and the gas charging opening; one end, close to the air charging opening, of the lever is slidably connected with one surface, far away from the air charging opening, of the cover plate in a leaningmanner; and after rotating, the lever is used for pushing the cover plate to rotate until the cover plate is hermetically connected with the sealing plane in a leaning manner.