Ammonium phosphate fire extinguishing agents, due to their excellent cost-effectiveness and suitability for forest fires, have become one of the most commonly used fire suppressants for forest fire control. Among them, NH4H2PO4 fire extinguishing agent is the most widely applied. In this study, NH4H2PO4 (>90%) as the main component of dry powder fire extinguishers was selected as the suppressant to investigate the reaction mechanism of NH4H2PO4 interacting with red pine wood pyrolysis gas flames. Initially, we constructed a Bunsen burner experimental system suitable for NH4H2PO4/red pine wood pyrolysis gas/air. Although experimental methods yield the most intuitive empirical conclusions, measuring only the laminar flame speed of red pine wood pyrolysis gas/NH4H2PO4/air mixture does not adequately analyze the inhibitory mechanism of NH4H2PO4 on red pine wood pyrolysis gas flames. Additionally, due to limitations in experimental equipment and methods, it is not feasible to extend equivalence ratios and NNH4H2PO4 doses to large or small working conditions. Therefore, in this study, we utilized Chemkin software to construct theoretical models of flames under different conditions and performed calculations. We comprehensively analyzed the kinetic regulatory mechanisms of NH4H2PO4 interacting with red pine wood pyrolysis gas flames from aspects such as chemical inhibition, sensitivity of elementary reactions, elementary reaction yields, and chemical reaction pathways. •The laminar flame velocity of NH4H2PO4 interacting with the pyrolysis gas flame of red pine was measured.•A comprehensive analysis of the dynamic regulation mechanism of NH4H2PO4 interaction with pyrolysis gas flame of red pine.•The inhibition mechanism of phosphorus-containing active substances on pyrolysis gas flame of red pine wood was elucidated.•Provide theoretical and experimental reference for development of more efficient fire extinguishing agents for forest fires.