A pharmaceutical composition for treating leukemia, mainly made of the following raw materials by weight percentage: 2 to 8 percent of realgar, 25 to 42 percent of indigo naturalis, 50 to 60 percent of salvia miltiorrhiza, and 6 to 10 percent of heterophylla. The present disclosure improves the preparation method of salvia miltiorrhiza, reduces the amount of the adding water, the number of decocting times and the decocting time. Tanshiuone IIA extraction rate reaches 75%. The pharmaceutical composition of the present disclosure can treat leukemia, the complete remission rate reaches 92.9%, the curative effect is obviously improved, and the toxic side effects are greatly reduced.
