Convex mouth is a common clinical face shape, especially in the southern region, such as “Phoenix”, which is a typical convex mouth face shape. It is characterized by convexity of the teeth and upper and lower jaws, which causes the lips to curl up and has a great impact on the appearance. It is related to genetics and acquired environmental factors, such as chronic rhinitis and common mouth breathing, which can lead to the occurrence of a convex mouth, and can generally be orthopedically treated through surgery. The common causes of convex mouth include genetic factors and acquired environmental factors, such as pediatric rhinitis and adenoid hypertrophy.