【Abstract】 Objective To explore the effect on the body weight and the mucosa and muscularis mucosae thickness of the forestomach on Sleeve Gastrectomy（SG）model in Wistar rat, and to provide morphology base for the further study weight loss mechanisms of SG．Methods 20 male Wistar rats were randomly divided into two groups, 12 wistar rats underwent sleeve gastrectomy as SG group．8 male Wistar rat underwent a laparotomy and stomach manipulation as sham group．Preoperative weight of the rats was measured，Preoperative, postoperative every week within postoperative 4 weeks, and then every two weeks for weight measurement．Rats were killed 12 weeks after surgery，then made Paraffin sections, observed the morphological changes of forestomach by histological methods. Results All rats remained alive in sham group，10 rats remained alive in SG group．In sham group，weight gain was achieved obviously after operation，whereas in SG group，weight gain was achieved until the 2th week．From then on , weight gain in SG group was significantly lower than in the sham group （P < 0.05）． Postoperative forestomach in SG group rats compensatory dilatated, Morphometry results under light microscopy suggest that mucosa and muscularis mucosa thickness in SG group thinning than that of sham group ( P < 0.01 ), mucosal shallowing. Conclusion Observation on the forestomach morphology on SG model in Wistar rat may contribute to the further elucidation of weight loss and weight rebound mechanism in the rat model.