Warfarin is widely used in the prevention and treatment of thromboembolic diseases. But, there still remain challenges for its safe and effective application and for how to obtain its best anticoagulation in clinical practice. In recent years, warfarin pharmacogenetics studies showed that the genetic variants of the genes (CYP2C9, VKORC1 and CYP4F2) related to the pathway of warfarin metabolism and function could affect the therapeutic dose of warfarin dramatically, as well as the risks for bleeding complications. In this review, we focused on the studies concerning on the correlation of above genetic variants with warfarin related over-anticoagulation and bleeding complications, so as to provide clinical reference for individualized anticoagulation therapy.