Since lithium iron phosphate cathode material does not contain high-value metals other than lithium, it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of waste lithium iron phosphate cathode materials. Here, we describe a selective recovery process that can achieve economically efficient recovery and an acceptable lithium leaching yield. Adjusting the acid concentration and amount of oxidant enables selective recovery of lithium ions. Iron is retained in the leaching residue as iron phosphate, which is easy to recycle. The effects of factors such as acid concentration, acid dosage, amount of oxidant, and reaction temperature on the leaching of lithium and iron are comprehensively explored, and the mechanism of selective leaching is clarified. This process greatly reduces the cost of processing equipment and chemicals. This increases the potential industrial use of this process and enables the green and efficient recycling of waste lithium iron phosphate cathode materials in the future.