By using the most common bisphenol A epoxy resin Der331 as the matrix, then use methanal and cardanol to modify IPDA. It was determined by experiments that when the ratio of cardanol: methanal : IPDA was 1:1.1:1.2, the reaction time was 3h, and the reaction temperature was 90 C, the modified curing agent had the best performance. Compared with modified products and marketable products, the mechanical properties have been improved, and the anti-UV aging properties have been greatly improved. Verification in concrete shows that it can effectively improve the compressive strength of concrete. The product has excellent performance and broad market prospects.