Objective: To establish the living-mice colonoscopy platform, for providing a novel approach to study intestinal tumor in mice model. Methods: The living-mice colonoscopy platform was constructed by installing an URF-V fiber ureteroscope in the endoscope system, and then, 44 ApcMin/+ mice of 6- to 14-weeks old (characterized by spontaneous development of multiple intestinal adenomas) were used to conduct colonoscopic examination under anesthesia. The size and number of the adenomas were observed, and colonoscopic tumor scoring as well as tissue biopsy of the lesions were also performed. Results: Colonoscopic examination was performed 58 times in the 44 mice, 3 mice died, no intestinal perforation was observed, and the success rate was 99.71%. No tumor formation was discovered in only one mouse, while significant tumor was observed in all the other mice, and the mean tumor number and score was 3.60±1.52 and 3.26±1.29, respectively. Biopsy pathological examination showed that the lesions were intestinal tubular adenomas. Conclusion: The living-mice colonoscopy platform established in this study can be safely and effectively applied in colonoscopic examination for mice.