, a eurythermal and euryhaline species, is a commercially exploited crab inhabiting the southeastern coast of China. In recent years, mud crab aquaculture has suffered as a result of unsettled weather, which has led to a seasonal temperature and salinity changes in the sea water. This study aims to explore the molecular mechanism of cold tolerance in by examining the expression of adenine nucleotide translocase 2 () at different temperatures and salinities. ANT belongs to the mitochondrial carrier superfamily (MCF). It is the most abundant inner membrane protein of the mitochondrion and is responsible for the transport of ADP and ATP in the cytoplasm and mitochondrial matrix through the inner mitochondrial membrane. In this study, the relative expression of mRNA was detected using real-time quantitative polymerase chain reaction at different temperatures carapace width 3.7–5.8 cm, body weight 80–100 g) was expressed mRNA was lowest in the hepatopancreas, at a medium level in muscle, and highest in the gill, and the results indicated that the expression of mRNA decreased generally, but at 15℃the expression of <0.05)at different temperatures demonstrated that it might be associated with energy metabolism, and participate in stress responses at a certain range of low temperatures, stimulating in the mud crab. At the same temperature, the expression of at a salinity of 10 was significantly higher than at the higher salinity of 35 (<0.05), which indicated low salinity might be helpful for metabolism in mud crabs, enhancing cold resistance.ment to some extent.