Abstract：Objective：To observe the clinical effect of modified Simiao pills combined with western medicine for type IIIA prostatitis with dampness- heat stasis and stagnation syndrome. Methods： A total of 64 cases of patients with type IIIA prostatitis with dampness- heat stasis and stagnation syndrome were selected and divided into the study group and the control group according to the random number table method， 32 cases in each group. The control group was treated with levofloxacin tablets and tamsulosin hydrochloride sustained- release tablets， and the study group was additionally given modified Simiao pills based on the treatment of the control group. Both groups were treated for four weeks. The clinical effect in the two groups was observed. Before and after treatment，the changes in National Institutes of Health Chronic Prostatitis Symptom Index(NIH-CPSI) and the levels of white blood cell count，lecithin corpuscle count，Interleukin-1β(IL-1β)、Tumor Necrosis Factor- α(TNF- α)、Cyclooxygenase- 2(COX- 2) in prostatic fluid in the two groups were compared. Adverse reactions in the two gropus were observed. Results：The total effective rate was 87.5% in the study group，higher than that of 65.6% in the control group，the difference being significant(P＜0.05). After treatment，the total scores of NIH-CPSI in the two groups were decreased when compared with those before treatment(P＜0.05)，and the total score of NIH-CPSI in the study group was lower than that in the control group(P＜0.05). After treatment， the severity of inflammation in the two groups was reduced when compared with that before treatment(P＜0.05)，and the reduction in the study group was better than that in the control group(P＜0.05). After treatment，the levels of IL-1β，TNF-α and COX-2 in prostatic fluid in the two groups were decreased when compared with those before treatment(P＜0.05)，and the above three levels in the study group were lower than those in the control group(P＜0.05). Patients in the two groups had good tolerance，and so there was no serious adverse reactions and no obvious abnormality in liver and kidney function. Conclusion：Modified Simiao pills combined with western medicine for type IIIA prostatitis with dampness-heat stasis and stagnation syndrome can improve the severity of prostatitis，effectively alleviate clinical symptoms，enhance clinical efficacy，and provide a new treatment plan for treating chronic prostatitis with integrated Chinese and western medicine.