Compare investigate physicochemical properties of fine powder and two ultrafine powders of Dragon’s Blood, and then to determinate particle size distribution for ultrafine powders of Dragon’s Blood. Specific surface area and porosity, surface morphology and moisture absorption of Dragon’s Blood powders were investigated. The content and the in vitro dissolution of dracorhodin in Dragon’s Blood powders were determined by HPLC. The results showed that the content of dracorhodin had no significant difference among three Dragon’s Blood powders. With the decreasing of particle size the degree of moisture decreased. The dissolution of dracorhodin in the order of: ultrafine powder I > ultrafine powder II > fine powder. An appropriate degree of superfine grinding can improve moisture absorption of Dragon’s Blood powders and dissolution of dracorhodin. Particle size distribution of Dragon’s Blood ultrafine powder should be controlled about 40 μm.