An electric coolant pump, comprising a pump house; a motor connected to the pump house and comprising: a stator with a fixed central shaft; and a movable unit rotatably mounted within the stator, the movable unit comprising a support body, a bearing assembly connected to the support body, a rotor core fixed to the support body, a plurality of permanent magnets attached to the rotor core, the bearing assembly comprising at least one bearing rotatably supported on the central shaft; and an impeller housed in the pump house and driven by the motor; wherein the support body is formed by an injection-molding process with the bearing assembly and fixedly connecting with the rotor core, the bearing assembly comprises a cylindrical positioning sleeve and two bearings positioned at opposite ends of the positioning sleeve, the positioning sleeve and the bearings are sleeved on the central shaft, an inner diameter of the positioning sleeve is larger than that of the bearings, the two bearings are in friction fit with the central shaft, and the positioning sleeve is in clearance fit with the central shaft to prevent the positioning sleeve from interfering with the central shaft. a pump house; a motor connected to the pump house and comprising: a stator with a fixed central shaft; and a movable unit rotatably mounted within the stator, the movable unit comprising a support body, a bearing assembly connected to the support body, a rotor core fixed to the support body, a plurality of permanent magnets attached to the rotor core, the bearing assembly comprising at least one bearing rotatably supported on the central shaft; and an impeller housed in the pump house and driven by the motor; wherein the support body is formed by an injection-molding process with the bearing assembly and fixedly connecting with the rotor core, the bearing assembly comprises a cylindrical positioning sleeve and two bearings positioned at opposite ends of the positioning sleeve, the positioning sleeve and the bearings are sleeved on the central shaft, an inner diameter of the positioning sleeve is larger than that of the bearings, the two bearings are in friction fit with the central shaft, and the positioning sleeve is in clearance fit with the central shaft to prevent the positioning sleeve from interfering with the central shaft. a stator with a fixed central shaft; and a movable unit rotatably mounted within the stator, the movable unit comprising a support body, a bearing assembly connected to the support body, a rotor core fixed to the support body, a plurality of permanent magnets attached to the rotor core, the bearing assembly comprising at least one bearing rotatably supported on the central shaft; and an impeller housed in the pump house and driven by the motor; wherein the support body is formed by an injection-molding process with the bearing assembly and fixedly connecting with the rotor core, the bearing assembly comprises a cylindrical positioning sleeve and two bearings positioned at opposite ends of the positioning sleeve, the positioning sleeve and the bearings are sleeved on the central shaft, an inner diameter of the positioning sleeve is larger than that of the bearings, the two bearings are in friction fit with the central shaft, and the positioning sleeve is in clearance fit with the central shaft to prevent the positioning sleeve from interfering with the central shaft.