Abstract: CDAH2 resin was synthesized from catechol and chloroacetic acid as the main starting materials，its enrichment behavior for potassium ion was evaluated with a self-made exchange resin column. The improved synthesis process provides the resin with good adsorption ability for potassium ion in the exchange test solution with pH=4.0 at a temperature below 20 ℃ and an exchange flow rate of 2mL/min. The CDAH2 resin has a high recycling rate，and can be easily regenerated.