In order to investigate the effect of the energetic thermoplastic polyurethane elastomer (ETPE) with number average molecular weight of about 20000 as binder synthesized by 3,3-bisazidemethyl oxetane (BAMO) and 3-azidemethyl-3-methyl oxetan (AMMO) on the sensitivity of RDX-Al moulding powder,the contact angle of ETPE with RDX and Al powder was measured. The adhesion work and spread modulus between ETPE and RDX as well as ETPE with Al powder were calculated by the contact angle data. The scanning electron microscopy (SEM) photography and mechanical sensitivity of the explosive moulding powders with different contents of ETPE were observed and measured. The results show that in RDX-Al system,ETPE is easily coated on the surface of RDX particle. With increasing the dosage of ETPE from 2% to 5% in the RDX/Al system,the viscosity of the explosive system increases,the hot-spots are easy to form under the impact condition and the mechanical sensitivity of the explosive moulding powder increases from 0% to 40%,considering that when the ETPE with number average molecular weight about 20000 is used in pressed RDX-Al system explosives,the dosage of ETPE should be controlled within 5%.