Tris(4-iodophenyl)amine (TITPA) was synthesized using triphenylamine as raw material through electrophilic substitution reaction. Subsequently, a classic Arbuzov rearrangement reaction between intermediate TITPA and trimethyl phosphite was performed in a catalytic amount of Pd(PPh3)2Cl2 to obtain hexamethyl [nitrilotris(benzene-4,1-diyl)]tris(phosphonate) (TPTPA). The target product was characterized by 1HNMR、13CNMR、31PNMR、HR-MS and elemental analysis. The effects of catalyst type, catalyst dosage , reaction temperature and reaction time on the yield of the target compound were investigated. The results showed that the optimum conditions were obtained as follows: n(Pd(PPh3)2Cl2)∶n(TITPA) = 0.18∶1.00, reaction temperature of 150 ℃, reaction time of 5 h. Under these conditions, the yield of hexamethyl [nitrilotris(benzene-4,1-diyl)]tris(phosphonate) could reach 82.5%. Subsequently, TPTPA as a flame retardant was used for flame retardant modification of PVC. The results indicated that the prepared sample with an additive amount of TPTPA of 10% (based on the mass of PVC resin, the same below) had limited oxygen index of 29.6% and vertical combustion test of UL94 up to V-0 level as well as maintained excellent mechanical properties.