The brachial vein is the main deep vein of the upper extremity and is found on the medial side of the upper arm of the upper extremity, above the humerus. The brachial vein is generally connected to the brachial artery, and the brachial vein is divided into two branches, which are located on either side of the brachial artery. Most of the noble veins converge into the medial brachial vein at the midpoint of the upper arm, and there are cases in which the noble veins converge directly into the axillary vein. The radial vein and ulnar vein generally converge into the lateral brachial vein, and the two brachial veins travel up the brachial artery to the lower edge of the greater trochanteric muscle to converge into the axillary vein, and the two brachial veins can be connected with each other through the traffic vein when they travel up the upper arm, and the brachial vein is sometimes used for puncture to collect blood, which is a safe, reliable, and easy-to-perform method in the clinic and has a high success rate. Since the brachial vein is the main reflux vein of the upper limb, once a thrombosis occurs, it can easily lead to swelling of the upper limb and forearm, with should be immediately consulted, under the guidance of the doctor to standardize the treatment.