Abstract: DBA/2 mice i.p.transplanted with lymphocytic leukemic cells (L1210 cell line) were employed to study the effects of three extractions from Tephroseris kirilowii Turcz.Holub to the life span. It was at the first time found that the main chemicals in T. kirilowii are alkaloids and flavone, that the extraction prepared with 60 percent of ethanol solution performed the best effects on prolonging the life span of used mice.