An electric centrifugal pump, comprising a motor shell with an inner cavity hole in which a motor stator is installed, and a water pump shell installed on a front end surface of the motor shell, wherein the electric centrifugal pump further comprises an inner motor cover, a rear end of the inner motor cover penetrates through an inner hole of an iron core of the motor stator to stretch to a rear end of an inner cavity of the motor shell, the rear end of the inner motor cover is provided with an installation hole for installing a rear bearing of the motor rotor and a spiral overflowing hole, the rear bearing of the motor rotor is installed in the bearing installation hole arranged at the rear end of the inner motor cover, characterized in that, a chamfer is arranged at a front end opening of an inner cavity of the inner motor cover, an outside of a bearing pedestal is made into a conical surface, the conical surface of the outside of the bearing pedestal abuts against the chamfer at the front end opening of the inner cavity of the inner motor cover, the bearing pedestal is provided with an installation hole for installing a front bearing of the motor rotor and a spiral overflowing hole, the front bearing of the motor rotor is installed in the bearing installation hole arranged in the bearing pedestal, a shaft of the motor rotor is installed between the front bearing of the motor rotor and the rear bearing of the motor rotor, the motor rotor is fixed on the shaft of the motor rotor and located in a rotor cavity formed by the motor stator, a front end of the shaft of the motor rotor extends out of a front end surface of the front bearing of the motor rotor to stretch into an inner water inlet cavity of the water pump shell, a water pump impeller is tightly fixed on a front end journal of the shaft of the motor rotor through a water pump impeller insert, a water sealing bearing for isolating high and low pressure water cavities is arranged at an inner water inlet of the water pump shell, a boss in a circle is arranged on an edge of a front end center hole of the water pump impeller, a front end surface of the boss at a front end of the water pump impeller abuts against an end surface of an inner bearing ring of the water sealing bearing to isolate the high and low pressure water cavities, an axial portion of the shaft of the motor rotor is provided with a through hole penetrating through front and rear ends of the whole shaft of the motor rotor, a rear end of the shaft of the motor rotor extends out of a rear end surface of the rear bearing of the motor rotor to stretch to a leading impeller cavity enclosed by the rear end of the inner motor cover and the inner cavity of the motor shell, and a leading impeller is tightly fixed on a rear end journal of the shaft of the motor rotor through a leading impeller insert and located in the leading impeller cavity, wherein an internal forced cooling system is formed by the water inlet cavity of the water pump, the axial through hole of the shaft of the motor rotor, the leading impeller, the leading impeller cavity of the leading impeller, the spiral overflowing hole of the inner motor cover, the rotor cavity, the spiral overflowing hole of the bearing pedestal and the water pump impeller which are sequentially communicated with each other along an internal water flow, and the spiral overflowing holes (52, 62) are configured to reduce a flowing resistance of the internal water flow.