The present disclosure relates to the technical field of liquid sprayers, and more particularly to a multifunctional spray gun. The spray gun comprises a handle designed for single-hand four-finger ergonomic gripping and a pressing plate configured for single-hand thumb depression. The handle and the pressing plate are hingedly connected to enable more labor-saving and convenient single-handed operation. Additionally, a spray nozzle is detachably connected to the spray gun's discharge end to atomize liquid for spraying applications. Simultaneously, a foam spray head is detachably connected to the spray nozzle, converting atomized liquid from the spray nozzle into foam to achieve foam discharge requirements. When foam functionality is unnecessary, the foam spray head can be removed. Further, when atomization is unnecessary, the spray nozzle can be detached to discharge liquid only. The above design satisfies diverse liquid-discharging requirements across different scenarios, providing multifunctionality and convenient operation.