Four diagnostically challenging cases of unknown hepatopathy in four female diamondback terrapins（Malaclemys terrapin） are reviewed and important differential diagnoses discussed. The methods are necropsy，blood smear and histopathological section. At necropsy, the livers were dark，atrophied, and the capsule fibrotic. Abnormalities noted in the hemogram are eosinophilia. The number of leukocytes and eosinophils was significantly higher than normal ranges for healthy reptiles. The pathological changes of livers are the most serious and have consistency. Granular degeneration and vacuolar degeneration happened in most hepatic parenchyma cells, and seriously even necrosis. The hepatic veins lined by inflammatory cells and hepatic congestion. At the end, the most hepatic parenchyma cells were necrosis except the portal area. The lesions in eyelids, lung and kidney are mild and not enough to threaten life，and were complications. The lesion in the four terrapins was diagnosed on these results as a hepatopathy, and the terrapins died of liver failure. There is no evidence to prove that is a parasite infection.