The nasal septum is an important structure in the nasal cavity. The nasal septum has a scaffolding role and consists mainly of cartilage, bone and the mucoperiosteum on the surface of the nasal septum. The septum is mainly scaffolded by the septal cartilage, the vertical plate of the sieve bone, the plough bone and the nasal crest of the maxilla. The septum is above the bridge of the nose that can be felt with the hand, below at the base of the nose, connected to the nasal columella in front and behind until the posterior nostril. The nasal septum is not a piece of bone, it is composed of four pieces of bone together, therefore, the development speed of cartilage and bone sometimes is not the same, causing a certain piece of bone to grow faster, and the pressure generated is deviated to the side, and the most common disease that appears clinically is nasal septal deviation, which can cause nasal congestion and headache in severe cases, and it is necessary to perform nasal endoscopic nasal septum trilinear reduction method to treat nasal septal deviation.