Because of poor solubility in water, Ulifloxacin has low bioavailability. The invention relates to a novel Ulifloxacin mesylate, a preparation thereof, a kit comprising the medical antibiotic preparation, and application of the novel Ulifloxacin mesylate in preparing an anti-infective medicament. The invention specifically relates to a novel medicinal preparation which is used for injection and remains stable in storage; the chemical name of the preparation is 6-fluorine-1-methyl-7-(1-piperazinyl)-4-oxo-4H-[1,3]thiadiazolebutane[3,2-a]quinoline-3-mesylate. In the invention, injection and administration are carried out directly in the form of Ulifloxacin mesylate, and therefore solubility and bioavailability of Ulifloxacin are enhanced, and treatment effects of the preparation are improved simultaneously.