1. Types of nasal septal deviation (DNS): According to the morphology, there are four common types: “C”-shaped, “V”-shaped, “S”-shaped and wavy. However, there are also several special forms, such as caudal deviation (abnormal nasal column shape, nasal ventilation disorder, etc.), ventral deviation (crooked nose deformity, or with nasal septal deviation) and septal deviation of cleft lip and palate deformity. 2. Zoning of the nasal septum: It is recommended that the anterosuperior zone (cartilaginous part of the septum) be divided into two subzones, framed and non-framed, on the basis of Huizing’s four zones according to the surgical strategy, and this subzone constitutes the cartilaginous cone of the nasal bridge line and the structure of the nasal columella. The surgical guidelines have cautioned, the scope of taking septal cartilage, and postoperative nasal bridge collapse have confirmed the importance of dividing this two subzones. 3. Indications and objectives of surgery for deviated nasal septum: Surgery is the only treatment method. Indications for surgery: The deviation interferes with the physiological (ventilation, facial expression and aesthetic) function of the nasal cavity, and there are clear and specific symptoms and signs. The purpose of surgery is: to correct the deviated septum, to make the bilateral nasal airflow reciprocal, and to improve the nasal and sinus drainage channels. Surgical principles: first of all, good incision and exposure are needed to correct the septum, with as little cartilage and bone tissue removed as possible, so that the septum is in a median position. 4.Nasal septum surgical approach: as far as possible, perform the nasal approach surgery. 5.Septum surgery strategy: Non-frame zone DNS: submucosal correction of nasal septum (three-line subtension) or nasal endoscopy-assisted submucosal correction of nasal septum (three-line subtension); Frame zone DNS: nasal-septoplasty. 6, nasal – septoplasty (Septo-rhinoplasty): belongs to the external nasal approach, applicable to the ventral frame of the nasal septum or the caudal end of the nasal septum anterior dislocation, septal deviation with crooked nose (cartilage cone, bone cone deviation and nasal base nasal tip deformity.