AIM:To understand extraocular muscles image features in B-mode ultrasound.METHODS:The extraocular muscles on normal persons and different extraocular muscle diseases were observed using B-mode ultrasound from Oct.2007 to Oct.2010.RESULTS:Symmetric extraocular muscle thickness had no significant difference in normal eyes,the medial rectus was the thickest muscle among four rectus;before the age of 20,four extraocular muscles thickness increased with age.Different extraocular muscle diseases had different performance in B-mode ultrasound.CONCLUSION:B-mode ultrasound can show good form of four extraocular muscles and it is benefit for follow-up observation of extraocular muscle disease.B-mode ultrasound is an effective means of checking extraocular muscles.