A kind of foam spray gun, comprising a gun body, a
nozzle, a trigger, a one-way liquid inlet mechanism, a
piston rod, a
piston, a resetting piece, a one-way valve and 2 foaming screen meshes, said gun body being provided with a foam generating channel, said
piston sleeve being mounted on the inner side of said trigger and moving inward under the driving force of said trigger and engaged with said gun body, said piston being mounted on inner cavity of said piston sleeve and moving together with said piston sleeve and engaged with said gun body to form the first cavity and the second cavity, said one-way valve and foaming screen meshes being mounted inside the foam generating channel of said gun body. Compared with existing technologies, this patent is advantageous in that: it organically combines the foam generating mechanism formed by the one-way valve and one-way valve sidepiece with first cavity and second cavity of the gun body, allowing the liquid to be gathered at the liquid outlet of the one-way valve to form foams and then enter the screen mesh for secondary foaming, which ensures rich foams as well as reasonable and practical structure, moreover, it adopts the trigger type, which is simple and continent, labor saving and provided with fine
handle for repeatedly operation.