The utility model discloses an improved 280kw vertical water pump. The pump comprises a motor, a spindle, a pump body and a balance drum, the spindle and the balance drum are both located on the innerside of the pump body, the motor is connected with the spindle through a coupler, the balance drum is installed on the outer side of the spindle, a balance sleeve is installed on the outer side of the balance drum, and a filler sealing component and a thrust bearing component are further installed on the outer side of the spindle; the utility model discloses an improved 280kw vertical water pump.a cylindrical balance drum is mounted on the outer side of the main shaft; a balance sleeve is mounted on the outer side of the balance drum; a gap is formed between the excircle surface of the balance drum and the pump body; the pressure difference acting on the balance drum forms force opposite to hydraulic axial force to balance the axial force, the thrust bearing part can bear residual axialforce, the thrust bearing part is provided with an independent cooling pipeline, the cooling effect is good, the reliability of the circulating water pump can be improved through the whole design, thecontinuous operation time of the circulating water pump is prolonged, and meanwhile the maintenance cost is reduced.