In this work, a novel direct method, which was combined with reactive precipitation and liquid anti-solvent precipitation under high gravity environment, had been developed to prepare nanosized cephradine with narrow particle size distribution. Compared with commercial crude cephradine, the prepared cephradine showed a significant decrease in particle size, a significant increase in the specific surface area and shorter dissolving time when used for injection. The characteristic particle size was between 200–400nm. The specific surface area increased from 2.95 to 10.87m 2 /g after micronization. When the amount of l-arginin decreased from 0.25 to 0.18g, the mixture of nanosized cephradine and l-arginine could still dissolve in 1min. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the physical characteristics and molecular states remained unchanged after the recrystallization process. This method had potential application in industrial fields because of its low cost, efficient processing and the ease of scaling-up.