A spray quantity adjustable foam/liquid dual-purpose distribution device includes a gas compressor, an isolation electromagnetic valve, a liquid accumulator, an electromagnetic valve, and a foam generation device that are connected to each other. The gas compressor supplies pressurized gas into the isolation electromagnetic valve and/or the liquid accumulator or the foam generation device. When the pressurized gas is supplied into the liquid accumulator, an internal pressure of the liquid accumulator is increased to force liquid contained in the liquid accumulator toward the electromagnetic valve, which, once activated, conduct the liquid to the foam generation device, so that the pressurized gas and the liquid are mixed in the foam generation device to generate a foamed liquid that is discharged out through an egress opening.