Diffuser structure of water pump, it is mainly become by an outer barrel of awl shaft type and middle fixed connection's inner tube body group, outer barrel no. 1 intake the osculum tip and be provided with the flange and connect, the equipartition has a plurality of connect the via hole on the outer lane flange that the flange connects, the play water macrostoma end of outer barrel is provided with thickening connected pipe orifice to the equipartition has a plurality of screws on the connected pipe orifice terminal surface of thickening, the external wall of inner tube on be provided with the stator that the spiral was arranged to expand the ring shape conduit pipe of form outside being formed with between the inner wall of stator barrel outside and, this conduit pipe's tail end is formed with a transition circular arc in the thickening connected pipe orifice inboard of outer barrel and contracts the orientation in and go out the connected pipe orifice that the macrostoma was held, the hole that connects of flange be an inward throat outward to be formed with a throttle mouth of forming by interior draw mouth intaking the junction of osculum tip with outer barrel, it has simple structure, uses simple to operate, improves characteristics such as pump sending efficiency.