The invention discloses an intelligent automatic water purification system based on a PLC controller, which solves the problems of the filter in the prior art, which needs to be stopped for maintenance after failure, the pipeline water pressure is too high to shorten the service life of the pipeline, the purified water is prone to backflow, and automation low level problem. The present invention comprises a water delivery pipe for purified water, a first primary effect filter, a first fine filter, a reverse osmosis tank, an activated carbon filter, a centrifugal pump, a second primary effect filter, a second fine filter, a waste water collection tank, and a water supply pipe , the first booster tube, the first booster pump, the second booster tube, the second booster pump, a check solenoid valve, a pressure sensor and a PLC controller. The invention can carry out fault maintenance online, can effectively reduce the pressure in the pipeline connecting the fine filter and the reverse osmosis tank, prolongs the service life of the pipeline, saves the use cost, can effectively prevent the backflow of purified water, and can effectively improve the performance of the reverse osmosis tank Excellent reverse osmosis effect to improve purification efficiency and high degree of automation.