【Objective】 To investigate the feasibility of prostatic exosomal protein (PSEP) detection kit in the diagnosis of histological prostatitis (HP) in patients with benign prostatic hyperplasia (BPH), and to explore the correlation between PSEP and other clinical parameters. 【Methods】 A total of 104 patients with BPH or BPH plus HP treated during Nov.2021 and Nov.2022 were involved. The patients were instructed to fill out the International Prostate Symptom Score (IPSS) scale independently before surgery. Clinical data such as prostate volume, residual urine volume, free prostate specific antigen (fPSA), total prostate specific antigen (tPSA), and fPSA/tPSA were collected. Preoperative midstream morning urine was collected for PSEP detection. 【Results】 The sensitivity and specificity of PSEP in the diagnosis of BPH were 93.51% and 70.37%, respectively, which were highly consistent with the postoperative pathological diagnosis results (Kappa=0.663). Serum PSEP level was positively correlated with tPSA level (r=0.242, P=0.040). 【Conclusion】 PSEP has a high clinical diagnostic value in the diagnosis of HP, which can provide a reliable basis for the diagnosis of HP in BPH patients and improve the diagnosis rate.