The flame retardancy of wood is based on its chemical composition and structure. The objective of this study was to explore the （relationship） between the primary chemical properties of wood composition and its pyrolysis and combustion and to analyze the reaction path between the （reacting） flame retardants and wood composition. The conclusion showed that the key point was （temperature） at 200～300 ℃ where the flame retardant was able to promote dewatering and （charring） of wood. It also showed that a reacting type flame retardant was an efficient way to prevent the preservative from leaching. Finally, some suggestions for flame retardancy were made, such as （applying） Nanometer technology for wood flame retardant development and for exploring a versatile, efficient frothing type flame retardant.