Generally speaking, there is no absolute prevalence of renal pelvis separation on which side of the renal pelvis, and both left-sided renal pelvis separation and right-sided renal pelvis separation can be seen clinically. Separation of renal pelvis is commonly diagnosed in ultrasound report, which means that after ultrasound scanning of the kidney, the ultrasound image suggests that the renal pelvis is widened, and the diameter is usually larger than 10mm. Separation of the renal pelvis is seen in normal people, and holding in urine, bladder urination, etc. may lead to increased pressure in the urinary tract, which makes the renal pelvis widen. It usually improves with urination. It can also be seen in obstructive diseases of the urinary system, where poor urine drainage leads to urine retention, resulting in separation of the renal pelvis and widening of the renal pelvis. At this time, timely treatment is needed. It is recommended to go to the hospital in time when there is separation of the renal pelvis, clear diagnosis and targeted treatment.