the existing anti-CMV drugs mainly include valganciclovir, ganciclovir and foscarnet sodium, all of which act on DNA polymerase (pUL54), making them prone to cross resistance. DNA synthesis in normal cell is also catalyzed by DNA polymerase, which can also inhibit normal cell production, especially in metabolically active bone marrow cells, leading to bone marrow suppression. In addition, these drugs are mainly metabolized by the kidneys, causing damage to proximal renal tubular cells. Therefore, it is necessary to closely monitor the patient's renal function and adjust the dosage. Overall, the medical demand for effective and well-tolerated treatment methods for CMV infection management in kidney transplant recipients remains unmet, and safer anti-CMV drugs are urgently needed. The target of letemovir is the CMV DNA terminal enzyme complex, which is different from the target of existing anti-CMV drugs, and does not exhibit cross resistance. Moreover, this target does not have a corresponding substance in mammalian cells and does not exhibit toxicity similar to DNA polymerase targets. In addition, letemovir is mainly metabolized by the liver, and urinary excretion can be ignored (\<2% dose), so there is no need to adjust the dose according to renal function. Phase III registered clinical studies abroad have shown that letemovir is not inferior to valganciclovir in preventing CMV disease in kidney transplant recipients. Additionally, letemovir is safer and has a lower incidence of adverse reactions, especially leukopenia or granulocytopenia. However, there is still a lack of data on the use of kidney transplantation in Chinese population. The aim of this study was to evaluate the efficacy and safety of letamovir in preventing CMV infection and CMV disease in kidney transplant recipients in China.