Meares-Stamey’s “four-cup method” of classifying prostatitis was the first standardized method of classifying prostatitis by comparing the initial urine (voided bladder one, VB1), the intermediate urine (voided bladder two, VB2), the prostatic secretion (expressed prostatic secretion, EPS), and the post-prostate massage urine (voided bladder three, VB3), The results of the four cups of urine (voided bladder one, VB1), intermediate urine (voided bladder two, VB2), prostatic secretion (EPS), and post-prostate massage urine (voided bladder three, VB3) and the results of bacterial culture were used to classify prostatitis as follows Acute bacterial prostatitis (ABP), chronic bacterial prostatitis (CBP), chronic nonbacterial prostatitis (CNP) This classification reflects the past practice of classifying prostatitis as an infectious disease and prostatodynia (PD). This classification reflects the past understanding of infection as the main cause of prostatitis. In 1995, the National Institutes of Health (NIH) developed a new classification based on basic and clinical research on prostatitis: Type I: equivalent to the traditional classification of ABP. Type I: A disease with an acute onset, which may be characterized by a sudden onset of febrile illness with persistent and obvious symptoms of lower urinary tract infection, elevated white blood cell count in the urine, and positive bacterial cultures in the blood or urine. Type II: Equivalent to CBP in the traditional classification method, accounting for about 5% to 8% of chronic prostatitis. There are recurrent lower urinary tract infections lasting more than 3 months, elevated leukocyte count in EPS/semen/VB3, and positive bacterial culture results. Type III: Chronic prostatitis/chronic pelvic pain syndromes (CP/CPPS), equivalent to CNP and PD in the traditional classification, is the most common type of prostatitis, accounting for about 90% of chronic prostatitis. The main manifestation is prolonged and recurrent pelvic pain or discomfort lasting more than 3 months, which may be accompanied by varying degrees of urinary symptoms and sexual dysfunction, seriously affecting the patient’s quality of life; negative EPS/semen/VB3 bacterial culture results. Based on the results of routine EPS/semen/VB3 microscopy, the type can be subdivided into two subtypes, IIIA (inflammatory CPPS) and IIIB (non-inflammatory CPPS): type IIIA patients have elevated leukocyte counts in EPS/semen/VB3; type IIIB patients have leukocytes in EPS/semen/VB3 in the normal range. Subtypes IIIA and IIIB each account for about 50% of the cases. Type IV: asymptomatic inflammatory prostatitis (AIP). There are no subjective symptoms, and only evidence of inflammation is found during examinations of the prostate (EPS, semen, prostate tissue biopsy, and pathology of prostatectomy specimens, etc.). In addition to the addition of asymptomatic prostatitis, the above classification also combines the traditional classification of CNP and PD into one category, reflecting the new understanding of chronic prostatitis (type III) as a clinical syndrome. In addition, the division of type III into inflammatory (IIIA) and non-inflammatory (IIIB) subcategories, which are not equivalent to CNP and PD because of the expansion of the classification from EPS to EPS/seminal fluid/VB3 leukocyte counts, makes these two subcategories not equivalent to CNP and PD, respectively. The shift in the understanding of chronic prostatitis and the resulting new classification has shifted the treatment strategy to one that is symptom-based and more specific to the different subcategories. According to the International Prostatitis Collaborative Network (IPCN), after 3 years of clinical application, the classification is considered to be a significant improvement over the traditional classification, and has some guidance in clinical application, but there are still shortcomings that need further improvement. However, there are still shortcomings and further improvement is needed.