Abstract: The present invention relates to a drug for treating leukopenia, its preparation method and use thereof. The drug of the invention is prepared from 200-30 parts by weight of Folium Epimedii, 100-160 parts by weight of Fructus Psoraleae, 60-120 parts by weight of Radix Aconiti Lateralis Preparata (Processed), 200-300 parts by weight of Fructus Lycii, 200-300 parts by weight of Radix Astragali, 200-300 parts by weight of Caulis Spatholobi, 200-300 parts by weight of Radix Rubiae, 100-160 parts by weight of Radix Angelicae Sinensis, 200-300 parts by weight of Rhizoma Phragmitis, 100-160 parts by weight of Radix Ophiopogonis and 100-160 parts by weight of Radix et Rhizoma Glycyrrhizae. The drug of the invention comprises chemical substances with weight ratios as follows: Leucine:guanosine:psoralenoside:isopsoralenoside:calycosin-7-glucoside:liquiritin:icariin A:1,3-dihydroxyl-2-hydroxymethylanthraquinone:epimedin A:epimedin B:epimedin C:icariin:1,3,6-trihydroxy-2-methylanthraquinone:glycyrrhizic acid=(0.13-0.