A catalyst composition, a method for hydrogenating styrenic block copolymer employing the same, and a hydrogenated polymer from the method are provided. The method for hydrogenating styrenic block copolymer includes subjecting a hydrogenation process to a styrenic block copolymer in the presence of a catalyst composition. In particular, the catalyst composition includes an oxide carrier, and a catalyst disposed on the oxide carrier, wherein the catalyst includes a platinum-and-rhenium containing phosphorus compound.