The invention discloses a precipitation water treatment method. The method involves a folded plate eddy current synergistic flocculation unit, an inclined pipe precipitation unit, a sludge backflow and discharge unit and a dredge pipe backwash unit, wherein the folded plate eddy current synergistic flocculation unit is composed of four folded plate eddy current reaction chambers, raw water enters an water inlet pipe, passes through a pipeline mixer, and orderly passes through the four folded plate eddy current reaction chambers via a pipe mixer, and then enters the inclined pipe precipitation unit after passing through a transition area; same-wave folded plates, opposite folded plates and eddy current reactors in different models are arranged in the four folded plate eddy current reaction chambers, and a sludge backflow, discharge and backwash device unit is arranged at the bottom of each of the four folded plate eddy current reaction chambers. By use of the method disclosed by the invention, the efficiency of the flocculation reaction is improved, the effects of improving the water purification amount and the water quality are obvious, and the clarifying efficiency and the precipitation effect are guaranteed at the same time, water sources and the coagulation reagent quantity are effectively saved, and the high social and beneficial benefit are realized.