Objective:To explore the clinical features and treatment efficiencies of pediatric giant posterior fossa tumors.Methods:A retrospective analysis was performed. The clinical data of 18 children with giant posterior fossa tumors, whose maximum diameter of any section was over 5 cm, admitted to our hospital from January 2015 to June 2020, were collected. The surgical treatment results were analyzed.Results:The tumor volume of 18 children was (63.9±20.7) mL (33.2-116.2 mL). Sixteen children had different degrees of preoperative obstructive hydrocephalus; ommaya capsule implantation was performed in 2, ventriculoperitoneal shunt was performed in one, and external ventricular drainage was performed in one before surgery; intraoperative external ventricle drainage was performed in 5; and the left 7 had postoperative self-healing. Tumor resection was performed in 17 children, including 10 with total resection and 7 with subtotal resection. The postoperative pathological results indicated medulloblastoma in 10 patients, ependymoma in 3 patients, pilocytic astrocytoma in 2 patients, oligodendroglioma in 1 patient, and yolk sac tumor in 1 patient;12 patients were treated with chemotherapy and 9 with radiotherapy. Postoperative persistent hydrocephalus was noted in 2 patients, cerebellar mutism in 2 patients, and subarachnoid hemorrhage combined with ventricular hematocele in 1 patient. The follow-up period ranged from 3 to 67 months: 13 children survived for more than one year (10 lived without tumor recurrence); 8 of the 10 patients with total tumor resection had progression-free survival for more than 1 year (the other 2 patients were lost of follow-up), while 3 of the 7 patients with subtotal resection had progression-free survival for more than 1 year.Conclusion:Pediatric giant posterior fossa tumors have high complication rate, high recurrence rate and poor prognosis; symptomatic treatment, total resection of the tumors, and adjuvant radiotherapy/ chemotherapy are effective treatment methods.