A water pump for a vehicle comprising: a pump cover which forms an upper side exterior appearance of the pump for housing an impeller to be rotated; a hollow rotor coupled on the same axis with the impeller to rotate altogether; and a housing coupled to the pump cover to house the rotor and a stator therein, characterized in that the pump cover includes a first rotation shaft extended toward the hollow in the rotor passed through the impeller, the housing includes a second rotation shaft extended toward the hollow in the rotor, the first rotation shaft has a communication hole formed therein to be in communication with the hollow, the rotor has a communication passage recessed in a lower end portion thereof to a predetermined depth and the communication hole is formed to pass through the first rotation shaft in a center of the first rotation shaft such that water positioned on an upper side of the pump cover is able to be introduced to a lower side of the pump cover, wherein the first rotation shaft and the second rotation shaft have the same rotation axis, wherein the first rotation shaft is directed to one end of the hollow in the rotor, and the second rotation shaft is directed to the other end of the hollow in the rotor, and wherein the first rotation shaft and the second rotation shaft are arranged spaced from each other, wherein a portion of the water positioned on the upper side of the pump cover is able to pass through the first rotation shaft through the communication hole, and the portion of the water is able to move to the inside of the rotor, and is able to reach to the communication passage as the water moves down to a lower side of the rotor, and, the portion of the water positioned in the communication passage is able to move to an underside of the rotor, the water discharged to the outside of the rotor from the inside of the rotor through the communication passage is able to move to the upper side of the water pump along an outside circumferential surface of the rotor. a pump cover which forms an upper side exterior appearance of the pump for housing an impeller to be rotated; a hollow rotor coupled on the same axis with the impeller to rotate altogether; and a housing coupled to the pump cover to house the rotor and a stator therein, characterized in that the pump cover includes a first rotation shaft extended toward the hollow in the rotor passed through the impeller, the housing includes a second rotation shaft extended toward the hollow in the rotor, the first rotation shaft has a communication hole formed therein to be in communication with the hollow, the rotor has a communication passage recessed in a lower end portion thereof to a predetermined depth and the communication hole is formed to pass through the first rotation shaft in a center of the first rotation shaft such that water positioned on an upper side of the pump cover is able to be introduced to a lower side of the pump cover, wherein the first rotation shaft and the second rotation shaft have the same rotation axis, wherein the first rotation shaft is directed to one end of the hollow in the rotor, and the second rotation shaft is directed to the other end of the hollow in the rotor, and wherein the first rotation shaft and the second rotation shaft are arranged spaced from each other, wherein a portion of the water positioned on the upper side of the pump cover is able to pass through the first rotation shaft through the communication hole, and the portion of the water is able to move to the inside of the rotor, and is able to reach to the communication passage as the water moves down to a lower side of the rotor, and, the portion of the water positioned in the communication passage is able to move to an underside of the rotor, the water discharged to the outside of the rotor from the inside of the rotor through the communication passage is able to move to the upper side of the water pump along an outside circumferential surface of the rotor.