Abstract： Objective To explore the classification and surgical approach of magnum foramen tumor.Method A retrospective analysis was performed for 43 surgically treated patients with tumors involving the foramen magnum.According to the site of the tumor,the classification was divided to:Type Ⅰ ,located at dorsal, Ⅰ a extra - medullary, Ⅰ b intra - medullary, Ⅰ cintra - and extramedullary; Type Ⅱ,located at ventral, Ⅱ a extramedullary, Ⅱ b intramedullary.The midline approach was used in the Type Ⅰ (17cases), while the lateral or far- lateral approach for the Type Ⅱ (26 cases).Results Total excision was performed in 35(81% ).There were no mortality and no recurrence during the follow -up period.Thirtytwo patients had improvement in their neurological status, 3 cases unchanged.There were 8 cases aggravation,including newly cranial nerve deficits, hemiplegia, dyspnoea.Conclusions The preoperative classification was useful for the selection of surgical approach and evaluation of surgical outcome.The midline approach was apt to Type Ⅰ , while the lateral or far - lateral approach for the Type Ⅱ.