Graft-derived cell-free DNA (Gcf-DNA) is a non-invasive biomarker to monitor graft function. There are different methods to quantify Gcf-DNA, such as the classical Y-chromosome method and the latest digital droplet polymerase chain reaction method. In this study, we reported 2 patients genetically diagnosed with propionic acidemia (PA) went through living-donor liver transplantation (LDLT), and monitoring the change of Gcf-DNA examined by the amplification refractory mutation system polymerase chain reaction (ARMS-PCR) method. Two patients went through the operation successfully, and a 5 mL whole blood specimen was collected at 6 specific time points (day 0, day 1, day 7, day 14, day 30, day 60). The comparison of Gcf-DNA and the routine liver function showed that they have similar change-tendency curves, with the curves reaching the top at day 1 because of ischemia-reperfusion injury and generally declining from day 7-day 60 along with recovery of the patient. Applying the ARMS-PCR method to detect Gcf-DNA can be done without knowing the donor information and is not limited by donor-recipient-sex mismatch condition. In conclusion, Gcf-DNA is a promising biomarker that can monitor graft function in LDLT, and we will apply it in more samples and observe it long term to validate its efficiency in the future.