Abstract: The present disclosure provides a method for preparing lithium iron phosphate from ferric hydroxyphosphate, including: purifying ferrous sulfate to form a ferrous sulfate solution, adding hydrogen peroxide, phosphoric acid, an ammonium dihydrogen phosphate solution and ammonia water into the ferrous sulfate solution and then reacting to form a mixed slurry, holding the mixed slurry at a temperature for a period of time, and then washing with water and subjecting to press filtration to form ferric hydroxyphosphate precursors with different iron-phosphorus ratios; then flash drying, sintering at a high temperature, and pulverizing to obtain ferric hydroxyphosphate precursors with different iron-phosphorus ratios and different specific surface areas.