A preparation method of electrode materials for lithium batteries comprises the following steps: providing iron salt and a phosphorus source and dissolving the iron salt and the phosphorus source into a solvent to form mixed liquid; adding a plurality of micro particle packing into the mixed liquid, uniform mixing the plurality of micro particle with the mixed liquid, and regulating the pH value of the mixed liquid to be 1.5-5 during mixing to ensure the mixed liquid to react so as to form an iron phosphate precursor particles; providing lithium source solution and a reducing agent and mixingthe lithium source solution and the reducing agent with the iron phosphate precursor particle uniformly to form mixed slurry; and drying and heating the mixed slurry.