The invention discloses a handheld window-cleaning machine with a water spray prevention function. The handheld window-cleaning machine comprises a shell assembly with certain inside space, a suction nozzle assembly, a water tank assembly and a water-air separation assembly, wherein the suction nozzle assembly is connected to the front end of the shell assembly in a pluggable manner, the water tank assembly is used for collecting sewage, the water-air separation assembly is used for separating sewage from air, the suction nozzle assembly comprises a suction nozzle upper cover, a suction nozzle and a suction nozzle lower cover which are laid from top to bottom sequentially so as to form a sandwich structure, a groove sinking inwards is arranged at the lower part of the shell assembly, a containing chamber is arranged on the front part of the groove, the water tank assembly is embedded into the groove in a pluggable manner, and the water-air separation assembly is arranged in the containing chamber. The handheld window-cleaning machine with the water spray prevention function has the beneficial effects that while the cleaning efficiency of the window-cleaning machine is improved, the containing space of a sewage tank of the window-cleaning machine is increased, the water spray problem of the window-cleaning machine is solved, the window-cleaning machine efficiency of the window-cleaning machine is improved, and the user experience is improved.