Hexahydro-1,3,5-trinitro-1,3,5-triazine/resorcinol-formaldehyde (RDX/RF) aerogel and xerogel were prepared by supercritical fluid drying method and freezing drying method. The structure of RDX/RF composites were characterized by scanning electron microscopy (SEM),BET method,X-ray power diffraction (XRD) and differential scanning calorimetry (DSC). The results show that supercritical fluid drying method can get RDX/RF aerogel of typical nano-pore structures and high surface areas. Freezing drying destroys the framework of gels and leads to the rapid decreasing of surface areas of gels. The mean crystal size of RDX in RDX/RF aerogels is between 34-38 nm,and in RDX/RF xerogels is between 50-100 nm. The thermal decomposition temperature of RDX/RF aerogels decreases by about 14-25 ℃,and of RDX/RF xerogels decreases by about 2-7 ℃.