The brachial plexus nerve is complicated in structure, tortuous in shape, shallow in position, and dominates the movement and sensation of the upper limbs and shoulders.With the development of science and technology, the injury of brachial plexus nerve increases year by year.How to make a timely and accurate diagnosis of brachial plexus injury and make a clear distinction between pre-ganglia and post-ganglia injury before surgery have been the focus and difficulty of clinical research in recent years.This paper focuses on the development of high-frequency ultrasound in the diagnosis of different brachial plexus neuropathy.