The difference between decree lines and laugh lines is that the location is different and the reasons for their formation are also different. 1. Location: Decree lines are two lines extending down both sides of the nose, located in the combination of the nose, cheeks and upper lip line, bending downward and outward, gradually disappearing below the outer corners of the mouth. And laugh lines belong to a kind of wrinkles, generally distributed in the corners of the eyes and corners of the mouth and other parts, especially in the laugh wrinkles especially obvious. 2. Causes: Some people have congenital smile lines, but most of the patients have smile lines due to the relaxation and aging of the skin tissues with the increase of age. In addition, if the patient has maxillary dysplasia or often laughs and makes overly rich facial expressions, more obvious lines can also appear. The formation of smile lines is related to insufficient skin moisture, long-term sleep deprivation, improper use of cosmetics, etc. In addition, patients with poor mood, often moping, excessive smoking and drinking may also lead to aggravation of smile lines. It is recommended to strengthen skin care, pay attention to sun protection, maintain a balanced diet, live a regular life, insist on physical exercise, and keep a relaxed mood, etc. If the decree lines and smile lines are more obvious, affecting the patient’s facial aesthetics, they can be treated by a doctor in a timely manner.