Abstract: To compare the physical properties of ultrafine Dendrobium huoshanense Powder with different levels of granularity.The results showed that ultrafine comminution increased the flowability,wettability,bulk density,water-holding ability,expansibility and solubility of D.huoshanense powder. D.huoshanense ultrafine powder had greater degree of cell disruption,smaller particle size and more irregular shape than submicron powder.Ultrafine D.huoshanense powder was widely used in health food and pharmaceutical industries,help to improve the higher bioavailability.

Key words: Dendrobium huoshanense, ultrafine powder, physical properties, microscopic characteristics, scanning electron microscope