Abstract: Objective: To construct a model of acute and chronic dehydration in rats, the intervention conditions of the model was optimized, the improvement effects of pure water, tea drink, and low-sugar compounded electrolyte water on rats with acute and chronic dehydration were evaluated. Methods: Plasma volume, total plasma electrolytes, osmolality, CRE, BUN, and other markers were measured to determine the modeling conditions, such as dehydration time and volume. Acute and chronic dehydrated rats were administered pure water, tea drink and low-sugar compounded electrolyte water by gavage or free drinking respectively. The improvement effects of different rehydration were evaluated by comparing the above markers. Results: The modeling conditions for rats with acute dehydration were 60 h of dehydration, followed by an initial running speed of 10 m/min, which was gradually increased to 20 m/min within 10 min, with the exercise lasting for 30 min. The modeling conditions for chronic dehydration in rats involved restricting daily water intake by 50% for 14 d. Evaluation of rehydration in acute dehydrated rats revealed that after 4 h of gavage intervention, all three rehydration groups significantly improved the reduced plasma volume, total plasma electrolyte ions and elevated plasma osmolality in acute dehydration rats, with the low-sugar compounded electrolyte water showing better improvement. Additionally, the low-sugar compounded electrolyte water and tea drink groups significantly reduced the elevated levels of BUN and CRE in acute dehydrated rats, while the pure water group did not show a trend of recovery. Evaluation of rehydration in rats with chronic dehydration showed that after free drinking for 24 h, all three rehydration groups significantly improved the decreased plasma volume and elevated plasma osmolality in chronic dehydrated rats, with the low-sugar compounded electrolyte water showing more effective improvement. The low-sugar compounded electrolyte water also significantly increased the total plasma electrolyte ions in chronic dehydrated rats, while the tea drink and pure water only showed a trend of recovery. Furthermore, the tea drink and low-sugar compounded electrolyte water significantly reduced the elevated expressions of NGAL and CCL2 induced by chronic dehydration, indicating the alleviation of renal inflammation and injury. Conclusion: Low-sugar compounded electrolyte water could significantly restore the reduced plasma volume, electrolyte loss, and renal injury in rats with acute and chronic dehydration. The results of this study provided theoretical insights for the development of rehydration strategies for people experiencing acute post-exercise dehydration and long-term chronic dehydration.