The invention relates to a self-adjusting energy-saving centrifugal pump. The self-adjusting energy-saving centrifugal pump comprises a water-cooled motor, a support and a pump body. The water-cooledmotor is mounted above the support, the pump body is mounted below the support, and a mechanical seal is arranged at the position, corresponding to a rotary shaft, between the pump body and the support. The self-adjusting energy-saving centrifugal pump further comprises a sensor and a frequency conversion controller. The sensor is arranged on an outlet of the pump body and connected to the frequency conversion controller, the rotating speed of the water-cooled motor is controlled through the frequency conversion controller, a circulating water cooling passageway is formed in the support and the water-cooled motor, a filter net is arranged at the water inflow end of the circulating water cooling passageway, the water outflow end of the circulating water cooling passageway corresponds to themechanical seal, and water-cooled effluent can flush the mechanical seal. The fluid flow can be automatically adjusted, abrasion of the mechanical seal is reduced, the efficiency of the centrifugal pump is improved, and noise is lowered.