In this study, methane and model biogas were added during the catalytic steam gasification of pine to regulate the syngas composition and improve the quality of syngas. The effects of Ni/gamma-Al2O3 catalyst, steam and methane/model biogas on H-2/CO ratio, syngas yield, carbon conversion rate and tar yield were explored. The results indicated that the addition of methane/model biogas during biomass steam gasification could increase the H-2/CO ratio to about 2. Methane/model biogas, steam and Ni/gamma-Al2O3 catalyst significantly affected the quality of syngas. High H-2 content syngas with H-2/CO ratio of about 2, biomass carbon conversion >85% and low tar yield was achieved under the optimum condition: S/C = 1.5, alpha = 0.2 and using Ni/gamma-Al2O3 catalyst. According to ANOVA, methane and catalyst were the key influencing factors of the H-2/CO ratio and syngas yield, and the tar yield mainly depended on the Ni/gamma-Al2O3 catalyst. Biogas, as a more environmentally friendly material than methane, can also regulate the composition of syngas co-feeding with biomass. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.