Prostatitis, especially Chronic Prostatitis (CP) or Chronic Pelvic Pain Syndrome (CPPS) is one of the most common diseases of male urinary-genital system. Not only CP/CPPS has detrimental effects on male urinary and reproductive functions, but it can also result in strong mental distress because of its prolonged disease course. There are currently no objective diagnostic criteria for CP/CPPS and no accepted therapies that cure the disease. Its diagnosis depends heavily on self-described symptoms and a questionnaire survey for National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) as well as the exclusion of other urinary tract diseases. Therefore, a simple and efficient biological surrogate would significantly improve the diagnosis and aid in drug development and optimized treatments. PSEP (Prostate Exosomal Protein)-ELISA assay is a recently developed test that can quantify PSEP from the void urine. Multi-center clinical studies validated that CP/ CPPS patient’s present elevated PSEP level in urine when compared to the healthy men. Our previous work showed that the content of PSEP in chronic prostatitis sample was greater than 1.2 ng/ml which was much higher than the normal control. In this study, we further investigated the relationship between PSEP in urine and expressed prostatic secretion (EPS) indexes as well as NIHCPSI in CP/CPPS patients. From the claims data obtained from the three hospitals, we identified 372 patients with chronic prostatitis diagnosed from 2015 to 2018. Controls comprised 60 men randomly selected from health examination center in these hospitals. All samples conform to the ethical requirements of the hospital. Our study demonstrated a correlation between the increase of PSEP level and NIH-CPSI scores. Also the correlation was found between the PSEP level and EPS indexes. These findings highlight the potential of PSEP as a viable indicator of symptomatic progression of CP/CPPS. Applications of PSEP assay may guide drug discovery and lead to the better treatment to improve patient’s quality of life.