Disclosed are a hydrogenated styrene/conjugated diolefin copolymer, a foaming material thereof, and application thereof. The copolymer contains a styrene structure unit and a hydrogenated conjugated diolefin structure unit; by taking the total content of the copolymer as a reference, the content of the styrene structure unit is 15-50wt%, preferably 18-45wt%, the content of 1,2-polymerization structure unit in the hydrogenated conjugated diolefin structure unit is 8-32%, preferably 10-30%, more preferably 12-25%, the degree of randomness of the styrene structure unit in the hydrogenated conjugated diolefin structure unit is 30-80%, preferably 35-75%, and the degree of hydrogenation of conjugated diolefin in the copolymer is 85-100%, preferably 95-100%. The tensile strength at break of the hydrogenated styrene/conjugated diolefin copolymer is 30-60 MPa, the elongation at break is 300-600%, and the hardness (Shore A) is 70-98. Moreover, a foaming body having excellent performance including more than 60% rebound and less than 30% compression deformation can be manufactured by using a supercritical carbon dioxide foaming process.