Bladder spasm is a common and serious complication after prostate enlargement surgery, which mostly occurs within 3 d after surgery and is most serious within 24 h. It can be divided into complaining symptoms and observable symptoms. The main symptoms refer to the feeling of holding the bladder, urgent urge to urinate and stool, and painful bladder spasm. Observable symptoms refer to slowing down or stopping of drip rate during continuous flushing, occurrence of reflux or involuntary overflow of flushing fluid from the urethra. The degree of spasm is judged according to its clinical symptoms: 1. Asymptomatic: no urge to urinate, painful spasms, urge incontinence, and the number of spasms is less than 2 times per day. 2.Mild: slight sense of urge to urinate, cramping pain, occasional urge incontinence, number of cramps 2~5 times per day. 3.Moderate: obvious sense of urgency to urinate, painful cramps, occasional urge incontinence, number of cramps 5~7 times a day. 4.Severe: strong urge to urinate, painful cramps, frequent urge incontinence, the number of cramps does not exceed 7 times a day. Treatment measures: 1, active analgesia, hemostasis; 2, timely adjustment of the catheter, traction strength; 3, postoperative flushing fluid temperature should be maintained at 32 ~ 35 ℃, especially in winter should reduce the cold stimulation of the bladder; 4, eliminate tension factors, so that the patient’s whole body relaxation; 5, preoperative active prevention of urinary tract infection is also an effective way to reduce the cold on the bladder spasm.