Moringa oleifera leaf polysaccharides (MOLP) possess remarkable activities in glycemic and lipid regulation. Disorders of glucose and lipid metabolism are frequently accompanied by intestinal barrier impairment, whereas the protective effects of MOLP on intestinal epithelial cells and the intestinal barrier have not been systematically evaluated. In this study, the physicochemical and structural characteristics of MOLP under simulated gastrointestinal digestion were systematically investigated, and its protective effects on damaged intestinal cells and intestinal barrier were explored based on the Caco-2 cell model. The results showed that the main characteristic peaks of MOLP were consistently present without obvious peak shifts during in vitro simulated gastrointestinal digestion, and the overall molecular weight distribution remained relatively stable. No continuous and significant increase in reducing sugar content was observed. Monosaccharide composition analysis revealed only trace amounts of glucose and arabinose were released without obvious accumulation, indicating that MOLP maintained relatively stable physicochemical structure under simulated digestive conditions. In the ethanol-induced oxidative stress injury model of Caco-2 cells, compared with the model group, 200 μg·mL-1 MOLP significantly reduced intracellular ROS and MDA levels by 36.86% and 74.51% (P < 0.05), and markedly increased the activities of SOD, CAT and GSH-Px by 100.54%, 37.68% and 110.86% (P < 0.05), respectively. In the LPS-induced Caco-2 cell injury model, compared with the model group, 300 μg·mL-1 MOLP significantly decreased the levels of IL-6 and TNF-α by 45.78% and 52.28% (P < 0.05), and significantly elevated the IL-10 level by 37.54% (P < 0.05). Meanwhile, MOLP ameliorated the barrier function of inflamed intestinal epithelium and reduced epithelial permeability. Compared with the model group, △TEER was significantly decreased by 65.34% (P < 0.05), and the FD-4 permeability was reduced by 73.80% (P < 0.05). This study demonstrates that MOLP protects intestinal epithelial cells and intestinal barrier against oxidative stress and inflammatory injury, and provides a theoretical basis for the further development of MOLP as health food for intestinal barrier improvement.