Abstract: In order to investigate the pyrolytic characteristics of burning residue of fire-retardant wood,the multifunctional fire-resistance test apparatus aiming at simulating the course of fire was used to burn fire-retardant wood and untreated wood.Samples with different distance from the combustion surface were collected and the thermogravimetric analysis(TG) was applied to test the pyrolytic process of burning residue in an atmosphere of nitrogen.The results showed that:1) there was little difference between fire-retardant wood and its residue in the initial temperature of thermal degradation.The initial temperature of thermal degradation of combustion layer in untreated wood was higher than that in no burning wood sample;2) the temperature of flame retarder in fire-retardant wood was 200℃ in the differential thermogravimetry(DTG).The peak belonging to flame retarder tended to dissipate with time of burning;3) for the burning residue of fireretardant wood,the peak belonging to hemicellulose near 230℃ in the DTG disappeared and there was a gentle shoulder from 210℃ to 240℃;4) the main peaks of fire-retardant wood and its burning residue in DTG moved to a lower temperature by 100℃ than untreated wood and its burning residue.The rate of weight loss also decreased sharply and this is corresponding to the main peak decreased with an increasing in heating temperature when burning;5) the residual weight of fire-retardant wood at 600℃ obviously increased compared with that of untreated wood.Residual weight of burning residue increased markedly as the heating temperature increased when burning;and 6) there was a considerable difference in respect of thermal degradation temperature of no burning sample and burning residue between fire-retardant wood and untreated wood.