Abstract: The flowability of silicified microcrystalline cellulose was compared with a mixture of standard grade of microcrystalline cellulose and silicon dioxide in order to elucidate the flowability changes of materials due to the silicification process and effects on the preparation characteristics in the direct compression process. The flowability, angle of repose, Hausner ratio and parameters in Kawakita equation were determined. Flowability differences were analyzed using scanning electron microscopy and X-ray microanalysis. Also, model drug was selected to investigate the content uniformity under desirable compressing performance. The flowability of silicified microcrystalline cellulose was better than the corresponding physical mixture, and the mechanism of flowability improvement was different. Silicified microcrystalline cellulose had better ability to improve the content uniformity of low dosage formulations. In conclusion, silicified microcrystalline cellulose is an excellent co-processed excipient, helpful to promote and improve the tablet manufacturing level.