Abstract: In the study,small intestinal mucosal structure,muscular layer thickness and the distributions and numbers of intraepithelial lymphocytes（IELs） and goblet cells（GCs） from Sunit sheep at 6 months old age was determined by Histological and Histochemical methods.The results showed the length of Duodenum villus were the longest,its length attained（353.25±60.48） μm,the Jejunum and Ileum in villus length were（317.27±72.02） μm and（275.36±47.62） μm respectively,but there was markedly different between Jejunum and Ileum（P0.05）;In mucosal thickness,Duodenum were the thickest reaching（669.15±139.04） μm,the Jejunum and Ileum were（586.72±134.50） μm and（551.85±91.32） μm,Duodenum in thickness was extremely different comapared with that of the Ileum and Jejunum（P0.01）;In the thickness of muscular layer,Ileum was the thickest reaching（280.45±58.33） μm,Jejunum was（167.16±42.63） μm and Duodenum was（148.78±38.36） μm,the difference was marked among them（P0.01）;In the depth of crypt,Duodenum was the deepest reaching（309.36±74.21） μm,Jejunum was（286.23±57.23） μm,the difference was marked among them（P0.01）;In the value of V/C,Duodenum and Jejunum were（1.80±0.45） and（2.00±0.48） respectively,there was different between Jejunum and Ileum（P0.01）;In the number of IELs and GCs,all parts of intestinal mucosal layer were not significantly different（P0.05）.The conclusion could be made that the length of villus,the mucosal thickness and the depth of crypt were gradually become smaller,while the muscular layer thickness were gradually become greater in small intestine from anterior to posterior,but there were no change of IELs and GCs numbers in all parts of small intestine.