Objective To investigate the expression of RNA editase ADAR1 in the lymphocytes in rats’ spleen with liver transplantation rejection. Methods Thirty SD rats and 75 Wistar rats were included. Fifteen livers from Wistar rats were transplanted to 15 Wistar rats (isograft group), 30 livers from SD rats were transplanted to 30 Wistar rats (allograft group and allograft+FK506 group), and 15 of them were then intramuscularly injected with FK506, 2 mg/(kg·d), the other 15 Wistar rats were only operated similarly to the other rats without any liver transplantation (control group). Five rats were killed and their splenetic tissues were collected on day 3, day 5, and day 7, respectively. The expression of ADAR1 mRNA in lymphocytes of the spleen in acute rejection was detected by RT-PCR. Results Different performance of pathology was observed in all the liver and spleen tissues from the transplanted rats over time, especially in allograft group. The expression of ADAR1 mRNA in the allograft group was significant higher than that of isograft and allograft+FK506 groups （P＜0.001）, especially on the 5th day. Conclusion There was a significant positive correlation between expression of ADAR1 and the severity of acute rejection, but the mechanism by which ADAR1 affected the acute rejection is unknown and needs to be further studied. FK506 may inhibit the expression of ADAR1 and remarkably reduce the severity of acute rejection.