Composite particles of carbon nanotubes (CNTs) and Cu were prepared by a chemical reduction method. Characterization of Cu/CNT composite particles was performed by TEM, SEM, FT- IR, XRD, XPS, AAS, DTA and EDS. The results show that the surface of CNTs is covered by Cu particles, and that the diameter of Cu/CNT composite particles gets larger than that of CNTs. Furthermore, in the presence of Cu/CNT composite particles, the peak temperature of the high-temperature decomposition of ammonium perchlorate (AP) decreased by 126.3 degrees C, and the peak of the low-temperature decomposition disappeared. Compared with a sample of simply mixed Cu and CNTs, the peak temperature of the high-temperature decomposition of AP-Cu/CNTs composite particles decreased by 11.4 degrees C. Compared with Cu, the peak temperature of the high-temperature decomposition of APCu/CNT composite particles decreased by 20.9 degrees C. This work shows that the catalytic performance of Cu on the thermal decomposition of AP can be improved by compounding with CNTs.