This dataset supports the review article "Improving Syngas Quality through Biomass Gasification Operating Condition Optimization". It contains literature-compiled data from peer-reviewed publications on biomass gasification, including key chemical reactions, thermochemical conversion phases, syngas composition values (H₂, CO, CO₂, CH₄), and the effects of operating parameters such as gasification temperature, equivalence ratio (ER), and steam-to-biomass ratio (S/B) on syngas quality. A complete list of all 70 cited references with DOIs is also included.