The invention relates to a washing powder slurry spray gun. The washing powder slurry spray gun comprises a spray gun main body, wherein an outlet end and an inlet end are formed on the spray gun main body; a nozzle is arranged at the outlet end of the spray gun main body; the spray gun main body is transparent; a spray pipe is arranged in the spray gun main body; a part of the spray pipe is positioned on the outside of the spray gun main body; a filter plug is arranged on the spray pipe; a branch pipe is further arranged on the spray pipe; the branch pipe is positioned in the front section of the filter plug; the branch pipe is connected with a crusher; a suction pump is connected between the branch pipe and the crusher; an intelligent valve is further arranged at the inlet end on the branch pipe; a cleaning pipe is arranged at one side, near the inlet end, of the spray pipe; a water valve is arranged on the cleaning pipe; the nozzle comprises a main nozzle and an auxiliary nozzle, wherein the main nozzle is connected with the spray pipe while the auxiliary nozzle is connected with crusher, and a high pressure pump is further arranged between the auxiliary nozzle and the crusher. The washing powder slurry spray gun provided by the invention is novel in design, reasonable in configuration and flexible and convenient to operate, can effectively prevent washing powder slurry from blocking the spray gun, and can be immediately and efficiently cleaned. The washing powder slurry spray gun is energy-saving and environmental-friendly.