The invention discloses a recovery and reuse method of lithium iron phosphate waste of lithium ion batteries. The method comprises the following steps: recovering the lithium iron phosphate waste, performing acid leaching on the waste, and performing hydrothermal reaction on obtained leachate and sulfide to obtain iron sulfide particles; performing carbon thermal reduction on iron sulfide to obtain a carbon-coated ferrous sulfide composite. The composite can be used as anode materials of the lithium ion batteries and has better lithium storage performance. According to the method, scrap lithium iron phosphate with lower value is converted into the materials with higher value, and the recovery value of the materials is improved. The recovery rate of the method is high, the iron element recovery rate can reach 90% or higher, and the follow-up lithium element recovery rate can also reach 90% or higher.