Lateral ventricular tumor refers to the tumor in the lateral ventricular wall, choroid plexus and ectopic tissue. Because of the deep location of the tumor and its proximity to important neurovascular and nucleus pulposus, it is very difficult and risky to operate, so it is very important to prepare adequately before operation. In our department, microsurgical resection of lateral ventricular tumor has achieved good results. The first symptoms are progressive headache with vomiting, seizure, vision loss or visual field loss, psychiatric symptoms, and some without obvious clinical symptoms. The tumor is located in the lateral ventricle or growing outward from the lateral ventricle as seen by CT. If the lateral ventricle is enlarged, the cerebrospinal fluid can be slowly released by ventriculotomy to make the brain pressure drop and relax, and the cortex can be incised. After entering the ventricle, we should confirm the tumor base, the main tumor donor vessels (pre and posterior choroid plexus arteries are the main ones), identify the relationship between the ventricle peripheral structures, the lateral and inferior walls of the ventricle and the interventricular foramen area. Avoid excessive traction and electrocoagulation on the neurovascular vessels (especially the funnel area and thalamic veins). Tumor resection is performed in whole or divided pieces according to size, texture and blood supply, and postoperative pathological examination is performed. Revealing and opening of the foramen magnum is one of the key steps of lateral ventricular tumor surgery, and hyaline septal fistula is feasible if necessary. The ventricular drainage tube should be left in place for 3-7 d. If there is no intracranial infection in hydrocephalus, vp shunt is feasible. Total resection of the tumor is possible. After surgery, the clinical symptoms are significantly improved or treated to be controlled or improved or cured. Lateral ventricular tumors can be divided into two types: primary, which originates from the ventricular wall and intraventricular tissue, and secondary, which originates from the adjacent brain tissue and grows into or invades the lateral ventricles. Generally, they grow slowly and are mostly benign tumors with no special clinical symptoms in the early stage, but when the tumor increases and blocks the cerebrospinal fluid circulation pathway or compresses and invades the adjacent brain tissue structures, the corresponding clinical symptoms will appear. Most of the patients have unilateral or bilateral obstructive hydrocephalus, producing headache mostly in episodic and intermittent aggravation, which may be accompanied by forced head position, vomiting, gait disorders and mental changes, mental disorders and seizures, as well as vision loss, isotropic blindness of visual field, or motor and sensory impairment of limbs. The tumor site in the lateral ventricle is deep and adjacent to the neurovascular organization, nucleus accumbens and deep cerebral veins, which makes the operation risky. The microscopic operation can achieve the goal of complete resection of the tumor and minimal damage. Special attention should be paid to protect the ventricular wall, the thalamic veins, and the surrounding important structures such as the anterior thalamus and the lateral internal capsule. Microsurgical resection of lateral ventricular tumor experience and precautions: (1) The site, growth mode and blood supply of the tumor should be fully understood before surgery, and the approach with the least damage to brain tissue and the shortest surgical path should be chosen; (2) Reduce the stretching of brain tissue; (3) The sulcus gyrus approach can reduce the scope of damage to the cerebral cortex and protect the reflux veins on the surface of the cerebral cortex to avoid persistent cerebral edema after surgery; (4) The tumor (4) treatment, microscopic operation, low-current electrocoagulation to prevent heat damage to the surrounding brain tissue, separation of the arachnoid layer gap between the tumor and intracerebroventricular tissue, full use of the physiological space of the ventricles and the pathological space produced by the tumor cystic lesion to reveal the operative field; (5) exploration of the foramen magnum is one of the main steps in surgery, and if necessary, transparent septal fistula is feasible to establish cerebrospinal fluid circulation pathway and release hydrocephalus; (6) (6) Repeated flushing of physiological saline to clear the operative area to avoid residual blood fluid, small fragments of tumor and brain tissue and tumor capsule fluid in the ventricles; (7) Use of cotton sheets to protect the surrounding area during surgery to avoid blood flow into the ventricular system, and try not to use hemostatic gauze or gelatin sponge to stop bleeding to avoid postoperative drift and obstruction of cerebrospinal fluid circulation pathway; (8) Close observation of pupil, consciousness and vital sign changes is required after surgery; (9) The most important postoperative complications are infection and hydrocephalus, and the intracerebroventricular drainage tube should be removed as soon as possible for lumbar puncture placement.