The invention discloses a treatment method for waste lithium iron phosphate. The waste lithium iron phosphate material is pretreated, and the pretreated material is added to a phosphoric acid solution to react and then filtered to obtain a first filtrate and a first filter residue; the first filtrate is added to a sulfide reaction, and then filtered to obtain a second filtrate and a second filter residue; Add iron powder to the second filtrate, remove iron after stirring and reacting, add battery-grade lithium carbonate to the obtained iron-removing material, stir and react until no bubbles are generated, and obtain the reaction material; add the reaction material to a water-soluble organic carbon source, stir to disperse and dissolve , the obtained material is spray-dried in a spray dryer to obtain a dry material; the dried material is put into a roller furnace for calcination, and after crushing, mixing, screening and iron removal, vacuum packaging is obtained. The invention can realize the resource utilization of waste lithium iron phosphate, realize high-end circulation, and at the same time, have a high recovery rate of each element, produce less waste water, and obtain excellent performance of the obtained lithium iron phosphate.