Tacrolimus, an immunosuppressant used after liver transplantation, has a narrow therapeutic range and its pharmacokinetic variability complicates its daily dose assessment. Therapeutic drug monitoring after liver transplantation, which is the mainstay to clinical immue suppression adjustment, still has its short- age. The development of pharmacogenomics depends on genetic polymorphism provides more reasonable di- rections to individualized immunosuppressive therapy. At present, the researches of the therapy mainly focus on the genetic polymorphism of coding gene of P450, PgP and nuclear receptor.