Ciprofloxacin (CIP) hydrochloride as a broad–spectrum antibacterial agent has been widely used against Gram–negative aerobic bacteria. It has been found the antibacterial activity and bioavailability of nano–sized ciprofloxacin hydrochloride can be largely improved. In this study, we demonstrated the bacteriostasis rate of ciprofloxacin hydrochloride was nearly doubled through the formation of nanomedicines. To this end, a facile solvent–assisted mechanochemical synthetic pathway was proposed to fabricate diprofloxacin hydrochloride nanomedicines (nano–CIP), which were further evaluated for the antibacterial activity against Escherichia coli (E. coli). Results showed that the bacteriostasis rate of nano–CIP reached ca. 86.4% which was nearly 2–fold that of ciprofloxacin hydrochloride powder (44.2%). At the same time, antibacterial plate experiments revealed significantly superior antibacterial effect of nano–CIP than the CIP precursors, which was largely due to the increased contact areas at surfaces of nanomedicines. Overall, this work presented a facile and effective means to prepared nanomedicines with enhanced bacteriostasis effects and bioavailability, which were key for their practical applications in medicinal areas.