The PBAMO/GAP random block energetic thermoplastic elastomer (ETPE) was synthesized via a solution polymerization using poly(3, 3-bis(azidomethyl)oxetane) (PBAMO) as hard segment prepolymer, glycidyl azide polymer (GAP) as soft segment prepolymer, toluene diisocyanate (TDI) as curing agent, 1, 4-butanediol (BDO) as chain extender. The structure of the ETPE was characterized by IR, gel permeation chromatography (GPC) and X-ray diffractomer (XRD). Results show that, the number average molecular weight of the copolymer can be up to above 34000. The imino groups of carbamate in the elastomer form the hydrogen bond with azido group, and the crystallinity of PBAMO in copolymer is 16.6%. The optimal experimental conditions obtained by optimizing the synthesis process are determined as :in the chain extension stage, T=130 ℃, t=40 h, M_n (PBAMO)=4100, m(PBAMO):m(GAP)=1:1, R=1.0, w (TDI+BDO)=30%.