This invention provides a composition of polyhydroxylated metallofullerene compound and its application in the preparation of antitumor pharmaceutical. In one embodiment, metallofullerol comprising the formula, M@C.sub.2m(OH).sub.x, wherein M is selected from rare earth elements such as La or Gd; m is carbon atoms of 41 or 30; x is a number of hydroxyl group of from 10 to about 50. Actually, due to the reset of the neighboring hydroxyl, the numbers of O and H in Carbon cage are different, formula are thus written as M@C.sub.2mO.sub.xH.sub.y. Comparing to the clinical anticancer drugs such as Paclitaxel, Cyclophosphamide, and Cisplatin, metallofullerol of M@C.sub.2m(OH).sub.x or M@C.sub.2mO.sub.xH.sub.y has superior advantages of higher antitumor efficiency, low dosage, low toxicity, and better biocompatibility.