Abstract: Drosophila melangaster is one of the ideal models for evaluating the activity of natural products. In this study, an SDS-induced intestinal inflammation model of fruit flies was established to explore the improvement effects of different extraction methods (traditional water extraction and alcohol precipitation method and complex enzymatic hydrolysis-assisted deep eutectic solvent method) and different extracts of guava after separation and purification on intestinal inflammation. The results showed that the guava polysaccharides extracted by the complex enzymatic hydrolysis-assisted deep eutectic solvent method significantly increased the survival rate of intestinal inflammation fruit flies and reduced the intestinal wall permeability. After further separation and purification, the GPB-1 component was superior to the GPA component in terms of prolonging the lifespan of fruit flies, reducing intestinal wall permeability, restoring intestinal length and improving antioxidant capacity. This study established a natural product activity evaluation system using fruit flies as a model, covering the entire process of polysaccharide extraction, separation, purification and activity evaluation, and integrating knowledge from multiple disciplines such as biological science, food nutrition, food chemistry and instrumental analysis. It is highly comprehensive. This system not only helps students master natural product extraction techniques, activity evaluation and data analysis methods, but also provides a low-cost and ethically friendly practical platform for teaching, promoting students' knowledge transfer and comprehensive quality improvement.