A kind of bonding functional energetic thermoplastic elastomers (ETPEs) were synthesized as the binder of solid propellants using the mixture of chain extenders including diethyl bis(hydroxymethyl) malonate (DBM). The results showed that the mechanical properties of ETPEs decreased with increasing percent of DBM in the chain extenders. On the contrary, the work of adhesion between solid ingredients hexogen (RDX) and ETPEs increased. In order to test the comprehensive impacts of two elements, the RDX/ETPE propellants were prepared. The results showed when the percent of DBM was 25%, the overall properties of the propellants were optimum.