The invention discloses a pharmaceutical for treating cancer and a preparation method thereof. The pharmaceutical is prepared from taxus, reed root, shinyleaf pricklyash root, cicada slough, medicinai changium root, manyprickle acathopanax root, isatis leaves, polygala root, umbrella polyporus, hirtellous clover-shrub root, tortoise shell, poria, snakegourd fruit, alpine yarrow herb, common portulaca, arisaema tuber, zedoary turmeric rhizome, spatholobus stem, natural indigo, self-heal, long-noded pit viper, rhubarb, subprostrate soplhor root, dandelion, polyphylla, kosam seed, wild glossy ganoderma, centipede, giant knotweed, airpotato yam, Sichuan clematis stem, sun spurge, ricepaper plant pith, medlar, largehead atractylodes rhizome, garden burnet root, schisandra fruit, oldenlandia,daxie, pilose asiabell root, grassleaved sweetflag, lycoris, ledebouriella root, brown lily and TAXEL by mixing proportionally. The pharmaceutical can be used for treating various cancers, especially for treating advanced cancers such as leukaemia with high leucocyte content and cancer metastasis to bones.