The effect of interfacial contact conditions between cyclotrimethylenetrinitramine (RDX) and copper oxide (CuO) on the thermal decomposition kinetics of RDX was investigated in this study. CuO was deposited onto the surface of superfine RDX particles to form RDX@CuO core-shell structure through RF magnetron sputtering technology. The thermal decomposition characteristics of RDX, RDX@CuO and RDX-CuO ultrasonic mixture were studied through thermo-gravimetric method. Kissinger and Kissinger-Akahira-Sunose methods were used to obtain kinetic parameters of thermal decomposition processes. It was found that the temperature corresponding to maximum weight loss rate decreased in the order of RDX>RDX-CuO>RDX@CuO. However, the apparent activation energy of RDX decomposition did not show apparent difference for the two kinds of CuO-containing samples. The results indicate that the interfacial contact conditions between RDX and CuO have an effect on the thermal stability of RDX but do not alter the thermal decomposition paths of RDX.