Highly dispersed Ru/Al2O3 catalyst can be obtained by using ruthenium trichloride and aqueous ammonia in the catalyst preparation. The dispersion of Ru on the catalyst was improved 2 fold, as much as that on the catalyst prepared by conventional impregnating method. When the ammonia treated catalyst was subjected to the steam reforming of hydrodesulfurized kerosene with 0.1 ppm of sulfur, the kerosene was converted completely into hydrogen enriched gases for several hours at lower S/C ratio (S/C = 3.5) at 800 degrees C. When a ceria was doped in the catalyst system, the sulfur resistance was improved dramatically and as a result the hydrogen production from the hydrodesulfurized kerosene can be continued after 8000 h by using Ru/CeO2-Al2O3 catalyst with high performance.