The invention discloses a method for reducing the acid using amount in the extraction separation process of medium and heavy rare earth. According to the method, a solution containing medium and heavyrare earth chloride and obtained through extraction separation passes through a resin column filled with cross-linked polymer, so that a medium and heavy rare earth chloride solution after impuritiesare removed is obtained; the medium and heavy rare earth chloride solution obtained after the impurities are removed passes through an extraction section, and extraction liquid and raffinate are obtained; the extraction liquid sequentially passes through a washing section and a reverse extraction section, and a reverse extraction raffinate is obtained. A scrubbing solution used in the washing section is an inorganic acid solution with the hydrogen ion concentration being 0.05-0.2 mol/L, flow of the scrubbing solution input into the washing section is 0.1-0.8 L/min, strip liquor used in the reverse extraction section is an inorganic acid solution with the hydrogen ion concentration being 3-7 mol/L, and the flow of the strip liquor input into the reverse extraction section is 1.2-3.0 L/min.According to the method, the acid using amount in the medium and heavy rare earth extraction separation process can be reduced, and the influence on the clarification effect of the medium and heavy rare earth in a water phase and an oil phase of the washing section and the purity of the raffinate obtained through extraction separation can be avoided.