Abstract: In this study, to address the bottleneck problem of growth inhibition under high salt stress in Halomonas elongata, we conducted a systematic selection of protective factors that could relieve the effect of salt stress inhibition. The results showed that the addition of betaine was able to increase the biomass by 18%, which was significantly better than other osmotic regulators. Further, metabolic kinetic modeling analysis showed that the maximum specific growth rate (μ_max) of the bacterium significantly increased by 42% after the betaine addition, and the respiratory intensity increased by 118%. Carbon distribution statistics showed that ectoine synthesis was significantly weakened during the delayed phase after betaine addition, and carbon metabolism was shifted toward growth of the cells. Finally the analysis of intracellular key metabolites showed that the addition of betaine significantly reduced the levels of alanine, valine and leucine, revealing that it may enhance the salt adaptation capacity of Halomonas elongata by strengthening the metabolic flux of the tricarboxylic acid cycle (TCA cycle). This study provides a theoretical basis and process optimization strategy for the construction of an efficient expression system for halophilic bacteria under high salt environment.