The invention provides a water treatment and cyclic utilization system. The water treatment and cyclic utilization system comprises a shell body, wherein the shell body is internally provided with a flocculation cavity, a sterilization cavity and an adsorption cavity; a controller is arranged at the bottom of the shell body; a water inlet and a sewage discharging opening are formed in two sides ofthe flocculation cavity; a flow guide plate is arranged at the bottom of the flocculation cavity; a groove is formed in the bottom of a pipe opening of a blow-off pipe; the groove is formed in the shell body; a stopping block matched with the pipe diameter of the blow-off pipe is arranged at one end of the flow guide pipe; an elastic structure is arranged at the lower end of the stopping block; the groove is internally provided with a first induction contact and an electromagnetic adsorption device; the stopping block is provided with a second induction contact and an electromagnetic adsorption part; the flocculation cavity is internally coated with polyurethane composite coating; the adsorption cavity is provided with a water inlet; the adsorption cavity is internally provided with a plurality of porous adsorption carriers; an adsorption cavity water outlet and a high-pressure washing water inlet are formed in two sides of the adsorption cavity respectively; the sterilization cavityis internally provided with a rotary ultraviolet lamp; a reflection layer is arranged on an inner wall of the sterilization cavity; a water outlet is formed in the sterilization cavity. The water treatment and cyclic utilization system provided by the invention has an automatic dirt cleaning function, can be used for comprehensively removing impurities, removing bacteria and removing undesirable odor and has a good river water treatment effect.