Concentrated water recycling method and filtering system with concentrated water recycling function

The invention provides a recycling method capable of improving the concentrated water recycling rate and a concentrated water recycling system. The method comprises the following steps: collecting concentrated water obtained by reverse osmosis filtration into a vessel, releasing a certain amount of concentrated water from the vessel when a user opens a mixed water faucet, mixing the released concentrated water with raw water, and outputting the mixed water from the mixed water faucet. The release amount of the concentrated water is determined by virtue of the following mode: a microcomputer device recalls corresponding control parameters from a database according to the collected raw water pressure value, raw water TDS (Total Dissolved Solid) value, concentrated water pressure value and concentrated water TDS value so as to control the opening time and/or opening degree of a concentrated water release valve. The method is applied to the system. The method has the advantages of high recycling rate, easiness for realization, and the like; the system has the advantages of causing no influence on the service life of a reverse osmosis membrane, completely consuming the concentrated water generated each day, being high in automatic control degree and relatively simple in system constitution, and the like.