A spraying device used on a water pump comprises a water drain pipe, wherein the water drain pipe comprises an inner pipe (1) and an outer pipe (2); the outer pipe (2) is provided with a first inlet (21), a second inlet (22) and an outlet (23); the inner pipe (1) is arranged in an inner cavity (24) of the outer pipe; a water inlet (11) of the inner pipe (1) is communicated with the first inlet (21) of the outer pipe (2); the first inlet (21) is connected with a water outlet of a water drain pump (6); the second inlet (22) of the outer pipe (2) is connected with a pipeline (3) arranged in a water drain pool or a sewage discharge mire; the outlet (23) and the second inlet (22) of the outer pipe (2) are respectively communicated with a water outlet (12) of the inner pipe (1). The spraying device used on the water pump has the advantages that sewage is sucked in through the second inlet, the water pump does not need to be placed in the water drain pool or the sewage discharge mire, and corrosion to the outer surface of the water drain pipe from the sewage is avoided; meanwhile, as the water pump does not need to be placed in the water drain pool or the sewage discharge mire, the possibility that the water pump sucks the sewage is avoided effectively, and the water pump cannot be burnt out.