A gas differential pressure valve with single diaphragm, comprising: a body having an inlet channel, a first gas chamber, a second gas chamber, a third gas chamber, a first channel, a second channel and an outlet channel; a valve assembly disposed in the body, a part of the valve assembly extending out the body, wherein the valve assembly has a diaphragm, the diaphragm separates the first gas chamber into a first pressure chamber and a second pressure chamber, the first pressure chamber is connected to the second gas chamber and the third gas chamber respectively, the inlet channel is connected to the second pressure chamber, the first channel is connected to the second pressure chamber and the second gas chamber, the connection junction of the first channel and the second gas chamber is defined by a first valve port, one end of the second channel is connected to the second pressure chamber and the other end of the second channel is connected to the third gas chamber, the connection junction of the second channel and the third gas chamber is defined by a second valve port, the outlet channel is connected to the third gas chamber, the connection junction of the outlet channel and the third gas chamber is defined by a third valve port; a first solenoid valve disposed in the second gas chamber, the first solenoid valve having a first valve plug, the first valve plug disposed on the first valve port; and a second solenoid valve disposed in the third gas chamber, the second solenoid valve having a second valve plug and a third valve plug, the second valve plug disposed on the second valve port, the third valve plug disposed on the third valve port. a body having an inlet channel, a first gas chamber, a second gas chamber, a third gas chamber, a first channel, a second channel and an outlet channel; a valve assembly disposed in the body, a part of the valve assembly extending out the body, wherein the valve assembly has a diaphragm, the diaphragm separates the first gas chamber into a first pressure chamber and a second pressure chamber, the first pressure chamber is connected to the second gas chamber and the third gas chamber respectively, the inlet channel is connected to the second pressure chamber, the first channel is connected to the second pressure chamber and the second gas chamber, the connection junction of the first channel and the second gas chamber is defined by a first valve port, one end of the second channel is connected to the second pressure chamber and the other end of the second channel is connected to the third gas chamber, the connection junction of the second channel and the third gas chamber is defined by a second valve port, the outlet channel is connected to the third gas chamber, the connection junction of the outlet channel and the third gas chamber is defined by a third valve port; a first solenoid valve disposed in the second gas chamber, the first solenoid valve having a first valve plug, the first valve plug disposed on the first valve port; and a second solenoid valve disposed in the third gas chamber, the second solenoid valve having a second valve plug and a third valve plug, the second valve plug disposed on the second valve port, the third valve plug disposed on the third valve port.