Dioscoreae Rhizoma formula granules are made from decoction pieces by decocting， extracting， separating， concentrating， drying and granulating， which have the advantages of simple dispensing， convenient use and easy to take without decoction. However， because Dioscoreae Rhizoma is rich in starch and mucus components， its extract powder and formula granules are poorly soluble and difficult to dissolve or disperse completely within 5 min， and the insoluble material is difficult to dissolve completely even after 24 h in water， which affects the quality evaluation of the formula granules and medication psychology of patients. Therefore， by studying the dissolution process and mechanism of Dioscoreae Rhizoma extract and its formula granules， it was found that the special chemical composition of Dioscoreae Rhizoma， the denaturation of starch and its compounding with protein and other substances during the high temperature extraction process， and the contraction of coating membrane during the spray drying process were combined to form the special microstructure of coating membrane covering starch granules， and it is the root cause of poor solubility of Dioscoreae Rhizoma formula granules. Based on the research on the structure， property and function of the powder， this paper proposed a technical strategy to improve the solubility of Dioscoreae Rhizoma formula granules by powder modification process， and experimentally demonstrated that the modified Dioscoreae Rhizoma formula granules could completely dissolve within 2 min， which solved the technical problem and could provide reference for the improvement of solubility of other similar varieties， and promote the high-quality development of traditional Chinese medicine formula granule industry.