The invention discloses an automatic adjusting device and method for inhibiting cavitation of a centrifugal pump. The cavitation state of the centrifugal pump is judged in real time by monitoring theflow, the inlet and outlet pressure and the inlet temperature of the centrifugal pump in real time, a control unit calculates the device net positive suction head NPSHa and the required net positive suction head NPSHr through the temperature and the inlet pressure, and if NPSHa is smaller than or equal to NPSHr, an electric control valve is controlled to be continuously opened and stops acting till NPSHa is larger than NPSHr. High-pressure fluid is guided to a centrifugal pump inlet on a centrifugal pump outlet pipe according to the requirement, automatic adjustment can be achieved through theelectric control valve arranged on a liquid supplementing pipe, and the effects of increasing the centrifugal pump inlet pressure and improving and inhibiting cavitation are achieved. According to the automatic adjusting device and method for inhibiting cavitation of the centrifugal pump, different working condition requirements can be effectively met for automatic adjustment and inhibition on cavitation, the stable running range of the centrifugal pump is greatly widened, the cavitation state of the centrifugal pump can be effectively improved, and the wide application value is achieved.