Purpose: To quantify the size of the giant pediatric intracranial tumor (GPIT), analyze the character of GPIT and optimize the management of GPIT.Materials and methods: This study analyzes the clinical data of 36 cases of GPIT at a center from January 2015 to August 2020. The volume of GPITs were measured by 3D slicer software based on preoperative magnetic resonance imaging (MRI).Result: The mean volume of GPITs is 110.7ml, with the maximum volume 619.8ml and the minimum volume 27.3ml. Hemisphere held the largest mean volume of GPIT among all locations, including 7 cases whose volume is over 100ml. There is no statistical difference in volume of GPIT between sex. The most common sites of GPITs are hemisphere and cerebellum. Other locations include ventricle, sellar-parasellar region and cerebropontine angle. Medulloblastoma is the most common postoperative histopathological type, other types contain ependymoma, pilocytic astrocytoma, atypical teratoid rhabdoid tumor (AT/RT), choroid plexus carcinoma (CPC), choroid plexus papilloma(CPP), oligodendroglioma, primitive neuroectoderm tumor (PNET), immature teratoma and yolk sac tumor. 28 cases achieved total resections while 4 cases only achieved subtotal resections. The patient with giant immature teratoma died during the operation because of bleeding. High-grade malignant tumors indicate poorer prognosis.Conclusion: GPIT is a common disease in children with unfavorable prognosis, especially in high-grade malignant tumors like CPC, PNET and AR/RT. Volume measurement based on MRI is an effective approach to access and compare the sizes of GPITs. Operation can expend the survival periods of the patients. Surgical strategies should be chosen according to the location and pathological feature of the tumors.