Simultaneous dyeing and inflaming retarding treatment improves both the aesthetic aspects and the safety value of fast-growing tree species. This study investigated the effects of water bath temperature, dye concentration, flame retardant concentration and dipping time on dye uptake and limited oxygen index of simultaneously dyed and fire-retardant-treated wood veneer. Through comprehensive analysis, an improved process was obtained and wood with these improved properties was prepared. Analyses of chemical structure and thermal stability of prepared wood samples were conducted, as well as crystallinity and microscopic morphologies using Fourier transform infrared spectroscopy, thermogravimetric, plus X-ray diffraction and scanning electron microscopy and energy-dispersive X-ray spectroscopy. Results showed that dye uptake and limited oxygen index had a similar increasing tendency with increased water bath temperature and dipping time. Moreover, dye uptake improved upon addition of flame retardant, while limited oxygen index decreased as dye concentration increases. Flame retardant combined with the wood fiber and was in the absence of chemical reaction with the dye used. Dye and flame retardant molecules diffused into the cell cavity, wood vessel and aperture. Furthermore, the fire-retardant properties and crystallinity of wood simultaneously treated with dye and flame retardant were both improved.