The invention discloses a hydrodynamic-cavitation enhanced water treating apparatus, comprising a pretreatment unit, an enhanced cavitation formation device, a water feedback cycle treatment loop, a multi-parameter water quality detection/display system and a smart automatic control system, wherein the multi-parameter water quality detection/display system is composed of a pressure sensor, a redox potential sensor, a flowmeter, a pH sensor, a conductivity sensor, a dissolved oxygen sensor, a chemical oxygen demand sensor, a total organic carbon sensor, a temperature sensor and an LED (Light-Emitting Diode) touch display screen, all of which are orderly mounted in a water outlet pipeline; the two ends of the water feedback cycle treatment loop are connected to the front section of a water outlet electromagnetic valve and the front end of a water pump of a water inlet pipeline, respectively; and the water outlet electromagnetic valve and a cycle-treatment electromagnetic valve are connected to a programmable controller, respectively. The hydrodynamic-cavitation enhanced water treating apparatus is used for water treatment and purification, and realizes online detection and display of a plurality of water quality parameters and operating parameters therein and automatic control on the operation thereof by means of a plurality of sensors.