〔Abstract〕 Objective To analyze the effects of prostatic fluid costimulator B7-H3 and inflammatory oxidation indexes in patients with type Ⅲ Qianliexin capsule treated with prostatin combined with prednisolone. Methods A total of 296 patients with type Ⅲ prostatitis admitted to the First Affiliated Hospital of Henan University of Science and Technology from May 2019 to May 2021 were randomly divided into observation group and control group by random data table method, with 148 patients in each group. The control group was given oral tamsulosin hydrochloride and prednisolone tablets, the observation group was given Qianliexin capsule in addition to the treatment of control group, both groups were continuously treated for 4 weeks. The efficacy of the two groups were compared, the scores of national institutes of health-chronic prostatitis symptom index scale (NIH-CPS) and traditional Chinese medicine symptom (TCM) score as well as the levels of costimulator B7-H3, interleukin (IL) -6, IL-10, IL-17, tumor necrosis factor (TNF)-α, superoxide dismutase (SOD), malondialdehyde (MDA), cyclooxygenase-2 (COX-2) in the prostatic fluid were compared between the two groups before and after treatment. Results After 4 weeks of treatment, NIH-CPSI and TCM symptom scores in the two groups were lower than those before, and NIH-CPSI and TCM symptom scores in the observation group were lower than those of the control group, the differences were statistically significant (P < 0.05). The total effective rate of the observation group was 89.86%, which was higher than 70.27% of the control group, and the difference was statistically significant (P < 0.05). The levels of B7-H3, IL-10 and SOD in prostatic fluid in the observation group were higher than those in the control group, while the levels of IL-6, IL-17, TNF-α, MDA and COX-2 were lower than those in the control group, and the differences were statistically significant (P < 0.05). Conclusion On the basis of conventional therapy, Qianliexin Capsule combined with prednisolone in the treatment of type Ⅲ prostatitis can improve the therapeutic effect and relieve the immune inflammatory imbalance and oxidative stress damage of prostate tissue.