Increased bladder residual urine is one of the most important diagnostic tools for prostate enlargement. As a result of prostate enlargement, the patient has difficulty urinating. As the obstruction increases, the urine in the bladder is not completely emptied during each urination and remains in the bladder, which is called “residual urine”. The presence and amount of residual urine reflects bladder dysfunction. In the process of diagnosing and treating prostate enlargement, the measurement of residual urine is an essential step, and there are three methods of measurement: transabdominal ultrasound, catheterization, and intravenous urography. Etiology of bladder residual urine symptoms: The etiology of increased bladder residual urine is unknown and may be related to age-related hormonal changes. Multiple fibroadenoma-like nodules appearing within the periurethral region of the prostate may originate from the periurethral glands rather than occur in the true fibromuscular prostate (surgical envelope), which is squeezed aside by the growing nodules. The hyperplasia may involve the lateral wall of the prostate (lateral lobar hyperplasia) or the tissue at the lower border of the bladder neck (medial lobar hyperplasia). Histologically this tissue is glandular, interspersed with varying proportions of fibrous stroma. When the lumen of the urethral ducts in the prostate section is damaged, urine outflow is gradually obstructed, along with hypertrophy of the bladder forcing muscles, trabeculae formation, small chamber formation and diverticulae. Incomplete bladder emptying causes urinary stasis, which predisposes to infection and secondary inflammatory changes in the bladder and upper urinary tract. Urinary stasis predisposes to stone formation. Long-term obstruction, even incomplete obstruction, can cause hydronephrosis and impair renal function.