Objective: To investigate potential effects of vasoactive intestinal peptide(VIP) in colonic submucous plexus of mice with severe acute pancreatitis (SAP) complicated by gastrointestinal dysmotility. Methods: Twenty Sprague Dawley rats weighing 200~250 g were distributed into two groups: induced acute pancreatitis and control group. Acute pancreatitis was induced by intraductal infusion of 5% sodium taurodeoxycholate,and small intestinal impelling ratio were detected. Pancreatic lesion was scored. Whole mount samples of submucous plexus were prepared and stained with double immunofluorescence to observe the morphology of VIP neurons. The percentage of VIP neurons in the total neurons was calculated. Results: Compared with the control gourp,the small intestinal impelling ratio in the SAP group was significantly lower(P < 0.01),the score of pancreatic lesion was remarkably higher(P < 0.01),the VIP neurons were bigger and more deeply stained,and the nerve fibers between ganglions of the VIP were thicker,and the percentage of VIP neurons was significantly higher(P < 0.01). Conclusion: A high expression level of VIP neurons in colonic submucous plexus may be one of the nervous mechanisms underlying gastrointestinal dysmotility in SAP rats.