Objective To investigate the feasibility of side-to-side magnamosis of the colon in rats by transanal magnet placement, and provide a model preparation method for studying the mechanism of magnamosis of the digestive tract. Methods Ten Sprague-Dawley rats were used as animal models. After anesthesia, a small abdominal incision was made, and a daughter magnet and a parent magnet were placed into the proximal and distal colon through the anus, and the daughter magnet and parent magnet were attracted under direct vision. The operation time, intraoperative and postoperative complications, and magnet discharge time were recorded. After 4 weeks, the rats were euthanized and the anastomosis specimens were obtained. The diameter of the anastomosis was measured, and the formation of side-to-side magnamosis of the colon was observed by naked eyes and light microscopy. Results Side-to-side magnamosis was successfully performed in 10 SD rats, and all rats survived to 4 weeks after operation. There were no complications such as bleeding, intestinal perforation and intestinal obstruction during and after operation. The operation time was 12.25±1.90 min, the magnet discharge time was 5.30±1.16 d, and the diameter of anastomosis was 5.51±0.29 mm. Macroscopic observation showed that the mucosa of the colonic side-to-side anastomosis was smooth, HE and Masson staining showed that the mucosa at the anastomosis was continuous. Conclusion Side-to-side colonic magnamosis with a transanal magnet placement in rat is simple to perform, with a high success rate and minimal trauma. It can be used as an ideal animal model for histological study of magnamosis of the digestive tract