Iliac vein compression syndrome clinically refers to the left iliac vein compression syndrome, according to its anatomical characteristics, mainly the right iliac artery crosses the left iliac vein, because the iliac vein support is relatively weak. Therefore, after the compression of the iliac artery on the iliac vein, it will cause suffocation, adhesion or even occlusion of the iliac vein, causing a series of symptoms of venous hypertension in the pelvis or left lower extremity veins with impaired blood return, and some of them will be accompanied by a series of clinical symptoms such as venous insufficiency of the lower extremity, or even varicose veins or thrombosis.