Dendrimer bonding agent (DBA) was applied in PET systems under the existence of solid filler(HMX,RDX and AP) to form test pieces. The mechanical properties of these test pieces were detected so as to study the bonding function of DBA. Excellent mechanical properties of propellant test pieces were obtained by adding 0.4% DBA. It was found that ester group could improve the max drawing intensity effectively while nitril group can improve the drawing rate. Also,stress-strain curves were analyzed to further investigate the interfacial binding property of test pieces.