ObjectiveTo study the preparation technique of Apium graveolens L.capsules and to assess the quality of the prepared capsules. Methods and ResultsUsing moldability and fluidity of the granules as indices, we optimized the formulation of Apium graveolens L.capsules by mono-factor test, with the mono-factors including microcrystalline cellulose, aerosil and lactose. In the optimized formula, the contents of aerosil, microcrystalline cellulose and polyvinylpolypyrrolidone were 26%, 30% and 2%, respectively. The aerosil had a satisfactory adsorption for volatile oil, which is important to the viscosity, moldability and fluidity of the granules. Three batches of samples were made using the optimized formula,and the quality evaluation tests showed that mass variation, the moisture content and contents of flavonoids and phthalides all met the quality control criteria. ConclusionThe granules of capsules prepared in this study have satisfactory moldability and fluidity.The preparation technique is simple and the quality can be controlled, making it suitable for industrial production.