Abstract: A range of DBA/2 mice i.p.transplanted with lymphocytic leukemic cells (L1210 cell line) were employed to study the anti-leukemic effects of 60% ethanol extract from Tephroseris kirilowii Turcz.Holub in vivo, with a reference system of cyclophosphamide (CY), quercetin (QU) and monocrotaline (MO) which are in the category of compounds in Tephroseris kirilowii Turcz. Holub. The anti-leukemic effect in vivo was examined in the life span of the mice used and the ventroperimeter, the morphological change of L1210 cell in the ascitical mice, the states of leucocytes and marrow, respectively. It was at the first time found that the extract prepared with 60% of ethanol solution performed the best anti-leukemic effect in the aspects of the mentioned above in vivo, which is consistent with the anti-leukemic effects of MO and QU.