To explore the characteristics of energy metabolism in Macrobrachium rosenbergii and their relationship with locomotive abilities under salinity stress, an experiment with four salinity levels [0 (control), 4, 8, and 12] was conducted. Oxygen consumption rates, key energy metabolism enzyme activity levels in gills and muscles, and swimming and tail-flipping abilities were determined after 48 hours of salinity stress. The results showed that there were no significant differences in oxygen consumption rates as salinity increased from 0 to 4; however, the values were significantly higher in the 8 and 12 salinity groups when compared with those in the control group (0 salinity). There were no significant differences in the activity levels of hexokinase (HK), phosphofructokinase (PFK), and lactate dehydrogenase (LDH) in the gill among different salinity level groups. However, the activity levels of pyruvate dehydrogenase (PDH) and cytochrome c oxidase (COX) in the gill were significantly elevated as salinity increased from 0 to 8. Moreover, the activity levels of PDH and COX in the gill were positively correlated with oxygen consumption rates. The activity levels of HK, PFK, and LDH in pleopod and abdominal muscles did not change significantly when salinity increased from 0 to 8, but PDH and COX activity levels in pleopod and abdominal muscles significantly decreased under the same condition. Significant decreases in the activity levels of HK, PFK, LDH, PDH, and COX were observed as salinity increased from 0 to 12, either in pleopod or abdominal muscles. With regard to locomotion, swimming ability significantly decreased when salinity increased from 0 to 8; meanwhile, the same decrease for tail-flipping ability was observed at a salinity of 12. Swimming ability was positively correlated with PDH and COX activity levels of the pleopod muscles, whereas tail-flipping ability was positively correlated with the activity levels of HK, PFK, and LDH in abdominal muscles. Our findings indicate that as a response to salinity stress, M. rosenbergii increases its reliance on aerobic metabolism in the gill, as evidenced by the increase in oxygen intake. However, these physiological regulations reduce the enzyme activity levels associated with energy metabolism in muscles, resulting in observed decrease in swimming and tail-flipping abilities of M. rosenbergii.