Dietary contraindications after orthognathic surgery include hard foods such as beef jerky and nuts; spicy and stimulating foods; tobacco and alcohol. The diet varies in different time periods after surgery. 1. 1~2 days after surgery: most of them need to keep the gastric tube after surgery, and feed liquid food nasally for 1~2 days (according to patient’s specific situation). 2. Within one week after surgery: avoid eating food containing residue, and take fluids without residue as the main food, for supplemental nutrition, there should be various kinds of food, such as milk, soymilk, fruit juice, fish soup, meat soup, chicken soup and so on. 3. 1~2 weeks after surgery: you can eat semi-liquid food, such as porridge, egg custard, etc., to supplement high protein, high calorie, high vitamin food, to promote wound healing. 3. 3~6 weeks after surgery: you can slowly transition to solid food, such as noodles, wontons, etc., exercise chewing with teeth. 4. 6 weeks~3 months after surgery: Bone healing is basically completed, most of the food can be eaten, but care should be taken to avoid too hard food, such as nuts and lean meat. It is recommended that patients should gradually transition from liquid food to solid food after surgery, and during this period, they should not consume hard food, spicy and stimulating food, tobacco and alcohol, so as not to be unfavorable to wound healing.