The utility model discloses a water conservancy diversion nozzle for horizontal well well -flushing, including cylindric body, the lateral wall of body is provided with at least one guide plate alongthe axial, the lower extreme of body is connected with the nozzle, the upper end of body is connected with the joint that is used for being connected to well -flushing oil pipe. The utility model discloses a water conservancy diversion nozzle for horizontal well well -flushing, simple structure, convenient to use, safe and reliable through setting up the guide plate at the tool body outer wall, can support the sleeve pipe inner chamber center of tool body at the horizontal segment, through setting up the nozzle, can make the water squeezed into from the oil pipe high -speed spraying from the hydrophthalmia, play and carry out abluent effect to set inside pipe wall and shaft bottom.