Nanoparticle-stacked 1,1-diamino-2,2-dinitroethylene (FOX-7) microspheres were successfully prepared by spray-drying, and rod-shaped FOX-7 was obtained by the solvent/nonsolvent method for comparison. The microstructure features of samples were characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD), and the thermal properties were also investigated by differential scanning calorimetry (DSC). From the SEM analysis, the particle size of the rod- shaped FOX-7 is about 10 [micro]m, whereas FOX-7 microspheres having a particle size ranging from 1 to 5 pm are formed by stacking nanoparticles with size of 100-250 nm. The crystal form of the samples prepared by the two methods did not change. The thermal performance test results showed that the rd-shaped FOX-7 had no significant change compared with the raw FOX-7, while the nanoparticle-stacked FOX-7 microspheres had higher thermal stability.