Abstract: To address the poor visibility of submerged bleeding points during endoscopic surgery, which can extend hemostasis procedures, a method combining 4-LED illumination with a saturation-to-hue mapping algorithm is proposed for enhancing bleeding points visibility. With imaging specificity for tissue and blood of varying concentrations, four narrow-band LEDs synchronous lighting are used for imaging, replacing the conventional xenon light source. In the xyY color space, the saturation information of the image is stretched and then mapped to the hue, effectively increasing the color differences between submerged bleeding points and the surrounding areas. Vitro experimental results using rigid endoscopes on animal materials demonstrate that the enhanced images achieved significantly higher color difference between bleeding points and their surroundings than conventional white-light images (41.31>11.78). Saturation-to-hue mapping imaging (SHMI) effectively improves the visibility of submerged bleeding points and reduces the risk associated with endoscopic surgeries.