Frequent urination after prostate cancer surgery may be caused by drinking too much water, mental and psychological factors, swelling of prostate, infection and other factors. 1. Drinking too much water: after prostate cancer surgery, patients drink water frequently, which leads to the increase of urine production, and then they will urinate frequently after surgery, accompanied by the increase of urine volume. 2. Mental and psychological factors: after prostate surgery, the patient’s mental and psychological pressure is large, which may induce mental dysuria, frequent urination after surgery, but the amount of urination is relatively small, and it can return to normal after improving the mental state. 3. Swelling of the prostate: just a local prostatectomy, due to the damage caused by the prostate gland, can make the prostate gland localized swelling, pressure and stimulation of the urethra, there will be frequent urination. 4. Infection: not strictly carrying out aseptic operation during surgery or not taking good care after surgery may induce urinary tract infection diseases, such as cystitis or urethritis, which will cause frequent urination, accompanied by pain in urination and urgency of urination, etc. Frequent urination after prostate cancer surgery may also be caused by other factors. If frequent urination persists and is accompanied by other obvious discomforts, it is recommended to consult a doctor for examination and treatment to avoid delaying the condition.