The invention relates to a saturation hydrogenation method for cracking C4 and C5 fraction by petroleum hydrocarbons, the catalyst is a nickel-based hydrogenation catalyst, the hydrogenation technology condition is characterized in that the inlet temperature of a reactor is 30-50 DEG C, the reaction pressure is 1.0-4.0 MPa, the liquid volume airspeed is 1.0-5.0h<-1>, and the volume ratio of hydrogen to oil is 100-400; the nickel-based hydrogenation catalyst is prepared by using an active ingredient and an auxiliary agent ingredient loaded on a carrier, which comprises an main active ingredient Ni and an assisted active ingredients of Mg, Mo, Sn, X1 and the carrier X2, The catalyst has high hydrogenation activity, and can perform a hydrogenation reaction under low temperature, and has characteristics of good thermostability, water resistance and coking resistance. The hydrogenation method can obtain an especially excellent hydrogenation effect, and is especially suitable for saturation hydrogenation of C4 and C5 fraction cracked by petroleum hydrocarbons.