The change and the role of MAPK cascade pathway and P53 pathway after liver transplantation were explored. Thirty-four punctured donor liver specimens and 10 normal liver specimens were classified as group A (no rejection, n= 10), group B (mild/moderate acute rejection, n = 10), group C (serious acute rejection, n = 8), group D (chronic rejection/fibrosis, n = 6) and group E (control, n= 10). By using tmmunohistochemistry, the expression levels of mitogen activated protein kinase (MAPK), Ras and P53 proteins, and by in situ hybridization, MAPK and ras mRNA expression levels were detected. The results showed that the expression levels of MAPK and Ras proteins were increased by ts in groups A, B and C, and decreased by ts in groups D and E. The protein expression of P53 was higher in the treated groups. The expression of Ras,HSP70 mRNA was identical as that of protein. It is suggested that the MAPK cascade pathway and P53 pathway can protect the hepatocytes by different mechanisms after liver transplantation.MAPKs cascade pathway repairs hepatocyte injury or accelerates hepatocytes into proliferation or differentiation. P53 pathway blocks cell cycle within G1 phase to make hepatocyte repair or apoptosis to reduce disorder differentiation.