The invention provides a ternary catalysis system used for selective hydrogenation of a conjugated diene containing polymer. The ternary catalysis system comprises organic acid nickel, aluminum alkyl and an amino compound. The amino compound in the catalysis system and an organic acid nickel compound firstly form a complex product, and then the complex product and the aluminum alkyl are subjected to ageing processing, so that an optimal quantitative proportion relationship between Ni+ and Ni0 is achieved, and the hydrogenation activity of the catalyst is more stable. By adoption of the ternary catalysis system, the reaction of the conjugated diene containing polymer in the hydrogenation process becomes milder, and the hydrogenation efficiency and the hydrogenation degree of the polymer are finally improved.