With the development of the research in human genomics, it is well known that genetic polymorphisms(mainly single nucleotide polymorphisms) of the genes encoding drug-metabolizing enzymes, transporters, receptors and other drug target proteins are relative to interindividual differences in the efficacy and toxicity of many medications. On the basis of functional genomics and molecular pharmacology, pharmacogenomics is elucidating the inherited nature of these differences in drug response mainly by means of analyzing the genetic variations of DNA and monitoring the gene expression pattern. It can not only improve disease diagnosis and predict the potential drug response but also speed up drug discovery and its development which will be instructive for clinical drug therapy ultimately.