The biogas represents one of the most widespread renewable fuel, because it's obtained from different biomasses and, therefore, produced from a variety of organic raw materials involved in various sectors: ranging from zoo-technical to agro-industrial. Moreover the biogas is considered a carbon dioxide-neutral bio-fuel. This study focused on syngas production by tri-reforming of biogas over Ni/Ceria based catalysts (nickel content: 1.76wt% - 28.57wt%) prepared by a combustion synthesis. The structure of catalysts and the effects of the operative conditions (temperature, O2/CH4, H2O/CH4) on catalysts performances were investigated. The catalysts chemical-physical characterizations reveals that strong interaction between support and well dispersed nickel exists and that some part of nickel incorporates into the CeO2 support. The characterizations and the catalytic results suggest that the nickel loading, the coexistence of different nickel phases, the properties of the CeO2 support, as well as, the operative condition play very important roles in the catalytic activity of Ni/CeO2 catalysts strongly affecting the performances.