Abstract: This is an essay in the field of metallurgical engineering. Using waste lithium iron phosphate battery cathode powder as raw material, a study on lithium selective leaching with Na₂S₂O₈ as oxidant and low concentration acetic acid as aleaching agent was carried out. The effects of Na₂S₂O₈ addition, acetic acid concentration, leaching temperature, leaching liquid-solid ratio and leaching time on selective leaching of lithium were investigated. At the conditions of acetic acid concentration of 0.3 mol/L, Na₂S₂O8 addition of 1.1 times the theoretical amount, L/S ratio of 10 mL /g and room temperature leaching for 2 h, the leaching rates of lithium, iron and phosphorus were 98.05%, 4.49% and 2.46% respectively.