Ultrafine 2,2′,4,4′,6,6′-hexanitrostilbene(HNS-F) was prepared with obtained HNS-Ⅱ by recrystallization and vibration cavity comminute, and was characterized. Results show that the particle sizes of HNS-F distribute from 0.1 μm to 20 μm, and its BET specific surface area increases to 9.10 m²·g^-1. The differential scanning calorimetry (DSC) analysis and thermal decomposition kinetics calculation indicate, compared with HNS-Ⅱ, the melting point and enthalpy of decomposition of HNS-F increase, and its temperature of the exothermic peak decreases, and its activation energy decreases to 201.6 kJ·mol^-1. 50% threshold energy for slapper detonator charged with HNS-F decreases to 0.557 J.