The first is an acute infection of the urinary tract, which can lead to congestion and edema of the mucous membrane of the urinary tract, resulting in increased resistance to urination or increased bladder sensitivity, which can lead to symptoms of difficulty urinating, usually accompanied by urinary urgency, painful urination or increased urethral secretions. The second, male prostate hyperplasia is the most common cause of urinary difficulties, manifested as urinary effort, urinary bifurcation or urine can not form a line, manifested as dripping, mostly progressive appearance, with the age of symptoms gradually aggravated, until the development of the degree of inability to urinate. Third, if there are urethral stones, urethral tumors and other lesions that lead to urethral obstruction, then there can be difficulty in urination, which usually appears suddenly, accompanied by persistent pain in the urethra, accompanied by symptoms such as bleeding from the urethral orifice, which requires urethroscopy. In the case of patients who have had urinary stones, the sudden difficulty in urinating is mostly related to obstruction caused by stones discharging into the urethra.