In order to minimize the invasiveness of intestinal disease diagnosis and surgery, we propose an anchoring and extending micro-robot. The gait of the micro-robot was designed according to the biomechanical features of the intestinal tract. The locomotion condition showed that the anchoring capability and extending ability should be balanced to enhance locomotion efficiency. The mechanical and control system was designed and fabricated under the requirements of the locomotive model. The assembled micro-robot was 90 mm in length and 13 mm in diameter. The micro-robot prototype was tested in in vitro experiments; its locomotion efficiency was approximately 100% in an ideal environment, but around 50% in a pig's small bowel (20 mm in diameter). The in vitro experiment results demonstrated that the gait is feasible for locomotion in the small bowel although the diameter of the small bowel is a limiting factor.