Mycophenolate mofetil (MMF) is a cornerstone immunosuppressant in clinical therapy, such as organ transplantation. Because of the huge interindividual difference in genetic polymorphisms and some other, fixed-dose MMFtreated strategy can neither attain the targeted effective and safe MPA blood concentration nor satisfy the needs of individualized therapy, especially in children. The article reviews the value of genetic polymorphism of UGT, IMPDH, ABCC2, SLCO in MMF therapy in children to highlight its role in the precision treatment.