The invention discloses a pressure reducing valve installed on a
liquefied petroleum gas steel cylinder valve. The pressure reducing valve comprises a main body, wherein a rod groove is formed on oneside of the main body, a screw rod is arranged in the rod groove, a first spring is connected with the side, close to the main body, of the screw rod, a spring
cushion block is fixed to a side, away from the screw rod, of the first spring, a transmission film is arranged on the side, away from the first spring, of the spring
cushion block, and a low-pressure
air chamber is formed in the side, close to the transmission film, of the main body. The pressure reducing valve installed on the
liquefied petroleum gas steel cylinder valve is advantaged in that an
insertion block is set, an air inlet
pipe is made to rotate, the air inlet
pipe is connected with a
steel cylinder connecting
pipe through a thread structure, when a first notch and a second notch are located on the same horizontal plane,the
insertion block is moved into the first notch and the second notch to block the first notch and the second notch, and the situation that when the pressure reducing valve is used for a long time, athreaded structure formed by an air inlet pipe and a steel cylinder connecting pipe loosens, and fixation is unstable is avoided.