Objective: To investigate the impact of orthotopic liver transplantation on serum lipid and growing development in patients with homozygous (HoFH) or compound heterozygotes (cHeFH) familial hypercholesterolemia. Methods: Patients who were treated in Peking Union Medical College Hospital from August 2019 to August 2021, entered the rare disease database and underwent liver transplantation, were included in this single center retrospective cohort study. The height for age Z score (HAZ) and length for age Z score (WAZ) at birth, at the time of transplantation and one year after transplantation were calculated respectively by collecting demographic characteristics, clinical manifestations, echocardiography, lipid-lowering treatment, blood lipid level data and donor characteristics data of liver transplantation. The serum cholesterol level and growing development changes before and after liver transplantation were evaluated. Results: A total of five patients with HoFH or cHeFH, including two females, were included in this study. The median age was 10 years (6-22 years). The median follow up duration was 28 months (24-33 months). All HoFH or cHeFH patients in this study received the maximum daily dosage of the lipid-lowering drug combined with low salt and low-fat diet control treatment for at least 3 months before orthotopic liver transplantation. The average level of total cholesterol (TC) decreased by 27% compared with that before treatment, the level of low-density lipoprotein cholesterol (LDL-C) decreased by 21% after 3 months treatment. There was no intervention of lipid-lowering therapy after operation. One month after liver transplantation, the average levels of TC and LDL-C further decreased rapidly by 68% and 76% respectively. One year after liver transplantation, the level of LDL-C decreased from (17.1±1.6)mmol/L without any intervention before transplantation to (3.0±0.7)mmol/L, and remained stable thereafter. In addition, compared with no intervention before liver transplantation, the serum triglyceride (TG) level decreased after the maximum daily dosage of the lipid-lowering drug and low salt and low-fat diet control for 3 months ((1.88±0.27) mmol/L vs. (1.12±0.55)mmol/L, P=0.031), and the HDL-C level also decreased significantly ((1.95±0.49)mmol/L vs. (0.95±0.30)mmol/L, P=0.006) at the same time period. TG and HDL-C remained stable after liver transplantation during the 24-month follow-up period (P>0.05). One and two years after liver transplantation, there was no significant difference in height and weight, malnutrition and growth retardation between the patients in this cohort and Chinese children of the same age. Conclusion: Early liver transplantation is a feasible and effective treatment option for HoFH or cHeFH patients with extremely high serum low-density lipoprotein cholesterol levels.