Objective To explore the clinical value of high-frequency ultrasound in the diagnosis of nerve entrapment syndrome caused by internal and external cysts of peripheral nerves.Methods 27 patients with peripheral nerve cysts were examined with high-frequency ultrasound to observe the ultrasonographic features of peripheral nerve injury caused by internal and external nerve cysts. Compared with EMG and MRI, intraoperative exploration was taken as the standard.Results Ultrasound diagnosis of intraneural cysts was performed in 12 of 27 patients. The main ultrasonographic findings were banded cystic nodules in the nerves, with a longer range of upper and lower nerve involvement, and normal nerve fascicles compressed and displaced; In 15 cases of extraneural cysts, the main ultrasound findings were compression and deformation of the nerves, marked thickening of the proximal and distal inner diameters, unclear or disappearance of fascicular or sieve like structures, and clear demarcation between the cysts and nerves. 24 cases were consistent with intraoperative findings. The electromyography results showed that 23 cases were positive, mainly due to a significant decrease in nerve conduction velocity and amplitude. MRI examination was performed in 3 patients, and the results showed a cystic signal shadow in the nerve routing area, with unclear demarcation between the lesion and the nerve.Conclusion High frequency ultrasound can provide morphological evidence for nerve cysts and can be combined with the electrophysiological characteristics of electromyography to provide more imaging support for clinical use.