Objective To observe the clinical efficacy of Bazhengsan combined with levofloxacin in the treatment of female patients with lower urinary tract infection, and explore its mechanism in treating female with Dampness-heat Down-flowing.Methods A total of 141 female patients with lower urinary tract infection admitted to The Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine were selected as the research objects. By randomized control method, they were divided into Bazhengsan group, combined group and control group, with 47 cases in each group,respectively.The control group was treated with levofloxacin, the Bazhengsan group was treated with Bazhengsan, and the combination group was treated with Bazhengsan combined with Levofloxacin. All patients in the three groups were treated for 2 weeks. Before and after treatment, the TCM syndrome scores, urinary white blood cell count, urinary bacterial culture, serum levels of procalcitonin (PCT), C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) inflammatory factors, clinical efficacy and adverse reactions of patients were observed and compared.Results After treatment, TCM syndrome score, urinary white blood cell count, urine culture negative rate, PCT, CRP, IL-6, TNF-α and other inflammatory factors in Bazhengsan group and combination group were significantly improved compared with before treatment (P<0.01). Compared with the control group, the symptoms such as frequency of urination, urgency of urination, burning and stinging urethra, and yellow and yellow urine in the Bazhingsan group and combined group were significantly improved (P<0.05 or P<0.01), the urinary white blood cell count was significantly decreased (P<0.01), and the levels of inflammatory factors such as PCT, CRP, IL-6 and TNF-α were significantly decreased (P<0.01). The rate of urine culture turning negative in combination group was increased (P<0.05). Compared with Bazhengsan group, the urine white blood cell count in combination group was significantly decreased (P<0.05). The total effective rate of Bazhengsan group, combined group and control group were 85.11%, 93.62% and 76.60%, respectively. Compared with the control group, the effective rate of the combined group was higher (P<0.05). There was 1 case with adverse reaction of the three groups. Conclusion The clinical effect of the therapy of Bazheng Powder combined with levofloxacin was more significantly than that of the therapy of levofloxacin in the treatment of female patients with lower urinary tract infection (syndrome of damp-heat down-flowing ). The therapy of Bazheng Powder combined with levofloxacin can effectively improve the clinical symptoms such as frequent urination, urgency, urethral burning and tingling, and yellow urine, reduce urine white blood cell count, and improve the trans-negative rate of urine culture, while the mechanism of the therapy of Bazheng Powder combined with levofloxacin is closely related to the reduction of inflammatory response,and combined use of them show better effects than single. Therefore, the therapy of Bazheng Powder combined with levofloxacin is worthy of further clinical application