In order to reduce the glass temperature of star type energetic thermoplastic elastomers(SETPE) and enhance its pliability, a novel A_nB star type energetic thermoplastic elastomers(TSETPE) based on PBAMO/APP was prepared via a urethane reaction of functional prepolymers, using UPBAMO (monofunctionality poly(3, 3-bis-azidomethyl oxetane)) as hard blocks, APP (trifunctionality glycidyl azide polymer modified by polytetrahydrofuran with the number average molecular mass(M_n)of 4000~6000) as soft blocks, toluene 2, 4-diisocyanate as linking compound. The optimized time of blocking reaction of UPBAMO was determined as 2 h. Its performance were characterized by Flourier transform infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatograph and mechanical property test. The number average molecular mass (M_n) of synthesized TSETPE was 15000~19000, the glass temperature of TSETPE decreased from -16.9 ℃ to -24.3 ℃ and the elongation (20 ℃) of TSETPE improved from 44.5% to 652%~919% as compared with SETPE which had similar M_n. The application study show that the TSETPE has good compatibility with commonly used energetic materials such as hexogen, aluminum powder, nitroglycerine, etc. The melt cast PBX explosive based on the TSETPE holds high energetic characteristics, and its heat of detonation can reach 7411 J·g^-1.