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Hydrogen production from biomass pyrolysis is economically and technologically attractive from the perspectives of energy and the environment. The two-stage catalytic pyrolysis of pine sawdust for hydrogen-rich gas production is investigated using nano-NiO/Al₂O₃ as the catalyst at high temperatures. The influences of residence time (0–30 s) and catalytic temperature (500–800 °C) on pyrolysis performance are examined in the distribution of pyrolysis products, gas composition, and gas properties. The results show that increasing the residence time decreased the solid and liquid products but increased gas products. Longer residence times could promote tar cracking and gas-phase conversion reactions and improve the syngas yield, H₂/CO ratio, and carbon conversion. The nano-NiO/A1₂O₃ exhibits excellent catalytic activity for tar removal, with a tar conversion rate of 93% at 800 °C. The high catalytic temperature could significantly improve H₂ and CO yields by enhancing the decomposition of tar and gas-phase reactions between CO₂ and CH₄. The increasing catalytic temperature increases the dry gas yield and carbon conversion but decreases the H₂/CO ratio and low heating value.