Abstract: This paper was reported 13 cases tumors primary in brain stem from 1992 to 1993 in our hospital. Rewieving the routine sections stained with HE, according to Kernohan class: ficafion there are 9 cases of astrocytoma, one case of arachnoid cyst, 3 cases of pilocytic astroytoma. The pilocytic astrocytoma was discussed in detail based on the reference, we think that this kind of brain tumor is not uncommen. It should be given serious attention. Practically, it is a kind of astrocytomas for the sake of brain stem's anatomy trait shape the peculiar histological structure.And it is a low malignant tumor and has favourable Prognosis.