Meningoencephalocele is an underdevelopment of the skull base to form a bone defect at the base of the skull, and the meningeal brain tissue herniates out of the cranial cavity. Clinically, it is seen in adolescents, mainly manifested as soft masses in the nasal cavity, nasal root or medial orbital area or eyeball protrusion. With age, it is sometimes combined with cerebrospinal fluid leakage, that is, the fluid in the brain leaks into the nasal cavity through the defective skull base. Clinically, some are easily misdiagnosed as nasal polyps. CT or MRI of the sinuses helps to confirm the diagnosis. The traditional surgical approach is usually through an extra-nasal skin incision, but it leaves a visible facial scar. Nasal endoscopic resection of nasal meningoencephalocele and repair of skull base defects are the latest advances in nasal surgery, which is minimally invasive and has no facial scars. Case introduction Patient XX, 35 years old, was admitted to the hospital with watery nasal discharge from the right nose for two months. There was no nasal congestion or headache. Examination revealed a smooth new organism in the right nasal cavity, and biochemical examination of nasal secretion suggested cerebrospinal fluid, CT and MRI examination suggested “bone defect at the base of the skull (up to 2.0cm in diameter), and the nasal mass was connected to the intracranial brain tissue”. Clinical diagnosis: Nasal meningoencephalocele with cerebrospinal fluid leakage. Surgical method: endonasal endoscopic surgery, resection of nasal mass with imported power system, repair of bone defect area at the base of the skull with muscle and fascia, plus biogel, outer layer with gelatin sponge, and finally nasal filling with iodine spun gauze strips. The nasal gauze was removed after 12 days of postoperative infection prevention, cranial pressure reduction and bed rest. There were no further episodes of nasal watery discharge after the operation. Preoperative imaging Preoperative Postoperative The skull base mass was removed and the skull base defect was repaired.