Objective To evaluate the clinical efficacy and safety of pazufloxacin for the treatment of moderate and severe acute bacterial respiratory infections.Methods A multicenter randomized controlled trial was conducted to compare the efficacy and safety of pazufloxacin versus levofloxacin. Patients in the pazufloxacin group were treated with pazufloxacin (500 mg twice daily for 7 to 10 days), and patients in the levofloxacin group were treated with levofloxacin (300 mg twice daily for 7 to 10 days). Results A total of 134 patients were enrolled in the study, 68 cases in pazufloxacin group and 66 cases in levofloxacin group were assessable for clinical efficacy by full analysis set(FAS). At the end of the treatment, in FAS analysis the total cure rates and effective rates were 52.9% and 86.7% in pazufloxacin group, 57.6% and 87.9% in levofloxacin group, in PPS analysis the total cure rats and effective rates were 57.1% and 93.7% in pazufloxacin group respectively, 61.3% and 93.6% in levofloxacin group. The bacterial clearance rates were 92.5% and 94.3% respectively. There were no statistically significant differences between the two groups. Adverse reactions were observed in 16.2% of patients in the pazufloxacin group and in 16.7% of patients in the levofloxacin group. These reactions were mainly local stimulation, nausea and diarrhea. No serious adverse event was reported in either group. Conclusion Pazufloxacin is as effective and safe as levofloxacin for the treatment of moderate to severe acute respiratory infections.