In order to improve the safety performances of ammonium perchlorate-based molecular perovskite ((H₂dabco)[NH₄(ClO₄)₃], DAP), DAP with micro/nano particles were prepared by ball milling. The morphology and structure of the as-obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy (Raman). Thermal decomposition and impact sensitivity was investigated by thermo-gravimetric analysis-differential scanning calorimetry(TG-DSC) and GJB770B-2005 explosion probability method, respectively. The DAP obtained by ball-milling were micro/nano with ellipsoidal particles of 0.5-10 μm, which had relatively smooth surface and good phase stability. The peak temperature of thermal decomposition of micro/nano DAP was 370.6 ℃, which obviously decreased as compared with raw DAP(385.4 ℃). Futhermore, the impact sensitivity of micro/nano DAP(28%) was much lower than that of raw DAP (56%).