The invention discloses a phosphoric acid purification device, comprising an extraction device, a washing device and a back extraction device, wherein the extraction device and the washing device select a single-stage phosphoric acid purification device formed by a group of emulsifying machines and a group of phase separation equipment or a multi-stage phosphoric acid purification device formed by multiple groups of emulsifying machines and multiple groups of phase separation equipment; the back extraction device selects a single-stage phosphoric acid purification device formed by a group of mixers and a group of phase separation equipment or a multi-stage phosphoric acid purification device formed by multiple groups of mixers and multiple groups of phase separation equipment; a first-stage solvent inlet of the extraction device is connected with a light phase outlet of final-stage phase separation equipment of the back extraction device; a first-stage solvent inlet of the washing device is connected with a light phase outlet of final-stage phase separation equipment of the extraction device; and a continuous phase fluid inlet of the back extraction device is connected with a light phase outlet of final-stage phase separation equipment of the washing device. The device can strengthen mass transfer performance, improve purifying efficiency, reduce equipment investment and operating cost and occupy less area.