NOVELTY - Preparing a catalyst comprising at least one porous support and at least one metallic phase containing nickel and tin in a proportion such that the molar ratio of tin/nickel is 0.01-0.2, comprises: depositing nickel on the support to obtain a monometallic supported catalyst made of nickel; reducing the monometallic catalyst in the presence of at least one reducing gas; depositing, in gas phase and in the presence of the reducing gas, at least an organometallic compound of tin on the reduced monometallic catalyst; and activating the obtained solid in the presence of the reducing gas.    USE - The catalyst is useful for selective hydrogenation of polyunsaturated hydrocarbon charge (claimed).    ADVANTAGE - The process is cost effective and consumes less time for preparing catalyst with improved catalytic selectivity. The process avoids hydrogenation of aromatic rings present in polyunsaturated compounds such as aromatics, styrene and indene, which avoids runaway reactions and develops compounds with an aromatic ring from the selective hydrogenation process.    DETAILED DESCRIPTION - Preparing a catalyst comprising at least one porous support and at least one metallic phase containing nickel (Ni) and tin (Sn) in a proportion such that the molar ratio of Sn/Ni is 0.01-0.2, comprises: (a) depositing nickel on the support to obtain a monometallic supported catalyst made of nickel; (b) reducing the monometallic catalyst in the presence of at least one reducing gas; (c) depositing, in gas phase and in the presence of the reducing gas, at least an organometallic compound of tin on the reduced monometallic catalyst; and (d) activating the solid resulting from the step (c) in the presence of the reducing gas to obtain a supported catalyst having a metallic phase based on nickel and tin in which tin is present at 0.02-15 wt.% and nickel is present at 1-50 wt.%. An INDEPENDENT CLAIM is included for process for selective hydrogenation of polyunsaturated hydrocarbon charge comprising passing the charge on at least one reaction unit provided with the supported catalyst comprising the metallic phase.