In order to improve the efficiency of heat treatment and the fireproofing of treated wood, nitrogen phosphorus fire retardant(FR NP) was used as an accelerating medium. The poplar(populusbeijingensis) wood samples were pre impregnated by FR NP and then heat treated at 120160℃. Results show that surface decorating property of the modified poplar wood combined FR NP pre treatment with low temperature heat treatment(NP Ht) is enhanced. The limiting oxygen index(LOI) value of NP Ht wood is higher than 39.00% and smoke density rating(SDR) is lower than 40. Meanwhile, the wood surface color of modified poplar wood combined FR NP pre treatment with 150℃ heat treatment(NP Ht 150) is mostly close to that of poplar wood treated by 220℃(Ht 220). Compared with that of Ht 220wood, the surface hardness and bonding strength of NP Ht 150is improved by 3415% and 5350%, respectively. The treating duration decreased by 75%. The FR NP could accelerate the decomposition of wood chemical components during the low temperature heat treatment. However, the degradation degree of celluloses is lower than that of Ht 220wood, the processes of low temperature heat treatment enhances the distribution of FR NP in wood and the destruction level of the NP Ht 150wood cell wall is much lower than that of Ht 220wood.