The invention discloses a catalyst, in particular to a modified cation exchange resin catalyst, which pertains to an organic resin catalyst technical field. The invention adopts the sulfonation cation exchange resin in aromatic series as raw materials, cation exchange resin with sulfogroup partially aminated or partially quaternary ammonificated is prepared through an ammonificating reaction. The resin catalyst has the advantages that catalytic activity of the catalyst can be obviously improved and a bed-layer pressure difference can be controlled at relatively low level.