Reaction of β-chloroethanol with sodium azide gives β-azidoethanol which in turn reacts with phosphorus oxychloride (triethylamine as an acid-trapping agent) to form a novel compound—tri(β-azidoethyl) phosphate (TAEP). The structure of TAEP has been identified by IR,¹HNMR,MS and elemental analysis. TAEP is a colorless liquid with theoritical nitrogen content 41.3%,density (25 ℃) 1.337 g·cm^-3,n²⁵_D 1.484 0. The onset and peak temperature of TAEP decomposition measured by DSC (heating rate 10 K·min^-1,nitrogen atmosphere) are 199 ℃ and 248 ℃ respectively. Impact sensitivity of TAEP is 20% (hammer 10 kg，height 25 cm,sample mass (50±1) mg,25 tests).