The invention relates to a catalyst for selective hydrogenation of petroleum hydrocarbon, in particular to a catalyst for selective hydrogenation of cracked petroleum. The catalyst comprises a titanium oxide-aluminum oxide compound serving as a carrier and active ingredient metal nickel loaded on the compound carrier, wherein based on nickel atoms, the metal nickel accounts for 5 to 35 percent of the total weight of the catalyst; and the titanium oxide accounts for 5 to 40 percent of the weight of the titanium oxide-aluminum oxide compound carrier. Compared with a conventional catalyst of the same type, the catalyst has high low-temperature hydrogenation activity and is suitable for the selective hydrogenation process of a diolefin-containing fraction, particularly C6-C8 fractions, C8 fraction, C9 fraction and whole fraction of cracked petroleum. Moreover, the invention also relates to a preparation method and application of the catalyst. The catalyst can also be used for selective hydrogenation of alkynes or diolefins of other petroleum hydrocarbons.