The interactions for 3,3-bis(azidomethyl)oxetane/tetrahydrofuran copolymer (PBT) with hexanitrohexaazaisowurtzitane (CL-20), 3,4-dinitrofurazanfuroxan (DNTF), 1,3,3-trinitroazetidine (TNAZ) and ammonium nitrate (ADN) were studied by using pressure differential thermal analyzer (PDSC) and thermogravimetry-derivative thermogravimetry (TG-DTG). The results show that decomposition of CL-20 is accelerated by PBT, decomposition peak temperature of CL-20 in PBT/CL-20 is a drop in 33.7 ℃ compared with that of pure CL-20. A part of PBT is also accelerated to decompose for the effect of the CL-20 and (or) its decomposition products. Sublimation and volatilization of the DNTF and TNAZ may be restrained by macromolecule of PBT,and their decompositions are advanced about 100 ℃. Besides,PBT is also accelerated to decompose by the decomposed gas products of DNTF and TNAZ. The interaction for PBT with ADN and its condensed phase products is not evident,except for the restraint effect of PBT on the sublimation of AN as the products of ADN. However,the gas products of ADN exert an influence on the PBT and ADN.