Salinity is an important ecological factor in the environment. The geographical distribution of Chinese mitten crab, , is affected by the levels of salinity and dissolved oxygen (DO). These factors also affect the hatching, development, and larval growth of E. sinensis. To study the effects of salinity on the standard metabolism of , juveniles were added to bottles with different salinity levels (0, 4, 8, 12, 16, and 20) and kept under the following conditions:average water temperature, (24±0.5)℃; average DO is (8.12±0.23) mg/L; pH, 7.5±0.18. The oxygen consumption, CO₂ discharge, and NH₃-N excreted into the water in each bottle were measured every 0.5 h during the experiment. Then, regression analyses were conducted for the oxygen consumption rate, CO₂ removal rate, and NH₃-N excretion rate. The response of the juveniles was divided into three stages:the free movement stage (DO>2.33 mg/L), the survival stage (0.33 mg/L < DO < 2.33 mg/L), and the asphyxia stage (DO<0.33 mg/L). Salinity significantly affected the oxygen consumption rate, CO₂ discharge rate, and NH₃-N excretion rate of juvenile <0.05). However, salinity did not significantly affect the oxygen consumption rate, CO₂ discharge rate, or NH₃-N excretion rate ( at the asphyxia stage. The results also showed that the fat was the main energy source under high-DO conditions. Under low-DO conditions, fat and carbohydrates provided energy, and the proportion of protein decreased as energy-providing substances were consumed. Together, these results showed that salinity affects the behavior and metabolism of juvenile . The overall aim of this study was to obtain baseline information on the standard metabolism of juvenile .