With nickel nitrate γ-Al₂O₃ and ammonium carbonate, precipition of Ni/γ-Al₂O₃ by Deposition and Precipitation Method was applied to the catalytic hydrogenation of styrene-isoprene-styrene block copolymer (SIS). The catalysts and products were characterized by XRD, TEM, XPS, ^₁HNMR and DSC. The hydrogenation performance of SIS was investigated from the aspects of support type, load, reaction conditions and cycle times. The results showed that the catalyst showed the best activity when cyclohexane was used as solvent, reaction temperature was 140 ℃, and reaction pressure was 1 MPa. The block hydrogenation degree of polyisoprene reaches 85%, and the hydrogenation degree of the side reaction benzene ring is less than 10%.