By using bisphenol A epoxy resin as the matrix, cardanol and methanal were used to modify isophorone diamine(IPDA) curing agent. The results show that when the mass ratio of cardanol, methanal and IPDA is 10∶11∶12, the reaction time is 3h, and the reaction temperature is 90℃, the modified IPDA curing agent has the best performance. The modified IPDA curing agent not only meets the mechanical requirements of concrete repair, but also greatly improves its anti UV aging property.