A preparation method of a crosslinking-type aqueous binder for lithium-ion batteries. An organic carboxylic group-, amino group- or hydroxyl group-containing hydrophilic polymer, and a hydroxyl group-, amine group- or carboxyl group-containing water-soluble small-molecule crosslinker, both serve as starting materials of the aqueous binder, and can be crosslinked by esterification or amidation under coating and drying conditions of lithium-ion battery electrode slurry. The preparation method of the crosslinking-type aqueous binder is simple, without the need of modifying the current process or conditions for lithium-ion battery manufacture. The obtained electrodes have excellent binding capacity, flexibility, and elasticity.