Disclosed is an internal duodenal film, made of a biocompatible biodegradable or non-biodegradable material or/and a hydrophobic material, mainly consisting of an elastic ampulla (1) and a tubular portion (3), wherein the ampulla (1) contains a biocompatible bionic microarray adhesive sheet (2) capable of strongly adhering through urging direction without pricking into the intestinal tissue and capable of easy desorption and recovery. The adhesive sheet (2) has good stability, strong adaptability to the material and appearance, and good self-cleaning, without damaging and contaminating intestinal tissue, and it can be repeatedly adhered and desorbed, and mutually supports other components in function. When intestinal contents move, since there is no subvertical tractive force, the film will not be desorbed, and when the duodenal ampulla expands and inflates, since there is no contrary subvertical tractive force in the film, it will also not be desorbed, while when performing recovery, it can be easily desorbed and recovered through the subvertical forces. The internal duodenal film can be prepared into a medical instrument for the prevention and treatment of obesity and diabetes without damaging intestinal tissue.