A novel oxyfullerene hollow nanosphere of C.sub.xO.sub.yMn.sub.z (45.ltoreq.x.ltoreq.72, 18.ltoreq.y.ltoreq.42, 7.ltoreq.z.ltoreq.16; x, y and z are atomic percentages) has a large surface area and high thermal stability, and can be simply prepared by reacting fullerene with alkali metal hydroxide and KMnO.sub.4 or MnO.sub.2, and treating the resulting mixture with an acid.