Abstract: An ion exchange resin catalyst containing sulfonated styrene-divinylbenzene copolymer, a porous structure with micropore area and transfer pass networks, the transfer pass network is composed of main pass networks and branch pass networks, in non-swollen state, the pore size of the main pass network is 9.times.10.sup.3 -38.times.10.sup.3 nanometer and the pore size of the branch pass network is 20-150 manometer, the pore size of the micropore area pass is 5-20 nanometer, wherein the pore capacity of the micropore pass with the pore size of 5-10.4 nm is more than 50% of the total pore capacity of the micropore area, and the ratio of the pore capacity of the micropore area to that of the transfer network area is 0.25-1.1. The catalyst is useful to condense phenols with ketones.