Understanding wood combustion has become increasingly critical as fire safety engineering moves toward a performance‐based approach to building design. Although different kinetic models have been developed for wood burning, chemical kinetics remains a significant challenge for accurate prediction. This work has developed a novel multiscale model by implementing kinetic parameters calculated from molecular dynamics simulations using reactive forcefield into a kinetic model of wood burning. The calculated kinetic parameters of the main components in wood, namely, cellulose, hemicellulose, and lignin, are first utilized to model microscale thermogravimetric experiments for validation. Subsequently, the mesoscale and full‐scale fire tests have been simulated by the multiscale model. Furthermore, the fire properties of various wood species at different heat fluxes have been predicted and compared with results from the cone calorimeter test. Our multiscale model outperforms existing kinetic models in predicting wood combustion and can effectively discern the influence of chemical components on fire properties.