【】Objective? To explore the normal ultrasound manifestation and clinical significance of expressive muscles with lower mouth angle function in the lower part .Methods Using ultrasound to scan bilateral lip-cheeks in 60 healthy adults,researchers will analyze the anatomical structure within the sonogram .Results? Ultrasound images display the starting and ending points of the depressor anguli oris and depressor labii inferioris,ae well as the distribution of some platysma fibers,as well as the course of the facial artery and its branching point of the inferior labial artery.Out of 120 sides,8sides of the inferior labial artery originates from the facial artery and divides into two deep? and shallow branches to “clamp”the depressor anguli oris ,while the other 112 sides of the inferior labial artery run on the deep surface of depressor anguli oris.Muscle thickness at the midpoint of the male depressor anguli oris was 1.9(1.6,2.0)mm on the left and 1.91±0.26mm on the right. Muscle thickness at the midpoint of the female depressor anguli oris was 1.5(1.3,1.6)mm on the left and 1.58±0.23mm on the right. There was a statistically significant difference in thickness between males and females at the midpoint of the ipsilateral depressor anguli oris (left z=4.32,?<0.001;right t=5.25,?<0.001). Conclusion? Ultrasound can serne as an important imaging tool of understanding the anatomical structure of the lip-cheek,providing effective reference for improving plastic surgery and beauty of the lip-cheek.