From the theory that the spleen and stomach are the source of qi and blood, the relevance between blood deficiency and iron deficiency anemia, pathogenesis and therapeutic principle of blood deficiency syndrome, and clinical application of reinforcing spleen and generating blood to treat iron deficiency anemia are discussed in detail. It is believed that iron deficiency belongs to the category of blood deficiency of Chinese medicine, in which the main pathogenesis is deficiency of both qi and blood and weakness of spleen and stomach. The therapeutic principle is invigorating spleen and stomach along with nourishing qi and blood. To treat iron deficiency anemia, better clinical outcomes can be acquired and more side effects be reduced by reinforcing spleen and generating blood based on iron supplement.