After impregnating nickel from NiCl₂ solution onto γ-alumina, the concentration profile of nickel, an active material was measured by an electron probe micro-analysis（EPMA）. Experimental results showed that the distribution and amounts of nickel could be controlled by changing initial pH, concentration and temperature of the solution, and pretreatment conditions of the support. The impregnation mechanism of Ni/γ-alumina system could be explained satisfactorily by the deposition due to difference in solubilities of the active material in the solution which exists in the pore.