•The effects of air flow and steam flow on gas component were investigated.•The Ni–Al2O3 catalyst was used to study the catalytic gasification characteristics.•The effects of different metal oxide additives on gas component were compared.•The Fe2O3 added to Ni–Al2O3 catalyst shows the best catalytic effect.The pine biomass gasification under air and oxygen/steam atmosphere was experimentally studied in a fixed bed reactor. The effects of air flow, gasification temperature, oxygen concentration, steam flow and the catalytic cracking reaction temperature on production distribution were investigated. The results indicate that the H2 content reaches the maximum at the gasification temperature 850 °C for a given air flow. Comparing with air-gasification atmosphere, the lower heating value (LHV) of produced syngas is higher (up to 8.76 MJ/Nm3) under oxygen-enriched gasification atmosphere. And the introduction of steam to the oxygen-enriched gasification leads to a higher H2 content and LHV of produced synthesis gas. Additionally, the syngas content increases significantly with increasing catalytic cracking reaction temperature when Ni–Al2O3 catalyst was employed in catalytic cracking process. The results also reveal that the steam reforming reactions of methane and carbon dioxide are enhanced over Ni–Al2O3 catalyst. The effects of different loading of metal oxide additives to Ni–Al2O3 catalyst on the catalytic activity were discussed, and it is found that the Fe2O3/Ni–Al2O3 catalyst shows the best catalytic activity and the H2 content achieves the maximum value of 39.21 vol.%.