Abstract: Tacrolimus is the cornerstone immunosuppressant after liver transplantation, effectively reducing the risk of post-operative rejection. However, optimizing its clinical dosage remains a major challenge. Cytochrome P450 (CYP) 3A5 is the principal enzyme governing tacrolimus metabolism and therefore dominates the metabolic process of the drug. CYP3A5 genetic polymorphisms are a key determinant of inter-patient variability of metabolic capacities and adverse clinical outcomes. In this article the population-specific distribution of CYP3A5 polymorphisms, the principal factors modulating early tacrolimus metabolism after liver transplantation and the clinical implementation of genotype-guided individualized dosing regimens were summarized. The aim is to provide a theoretical foundation for precise tacrolimus dosing strategies in liver transplantation, explore the feasibility of personalized medication approaches, and promote the practice of precision medicine in the field of organ transplantation.