Objective　To observe the morphogenesis of mouse small intestine tissues and distribution of caliciform cells in embryo at different stages in order to provide morphological data for the development of mouse small intestine.　Methods　HE and PAS stain were used in the paraffin section of mouse embryo aged from embryo 13.5 day (E13.5 d) to postnatal 1(P1) day. Rseults (1) At E13.5d, the small intestine of mouse was differentiated, the mucosa, submucosa, muscularis, serosa appeared. (2) At E15.5 d, the epithelium of intestine started differentiating into intestinal villus, and caliciform cell gradually formed at the day E16.5 embryo, at P1 day embryo small intestinal gland builded up. At this time of embryo, the basic structure of small intestine came into being. (3)The number of the caliciform cells increased as mice age, that caliciform cells were most abundant at P1 day (P<0.05). Caliciform cells were distributed mainly over the epithelial villus, i predominate in the terminal ileum, and deminishing from ileum, jejunum to duodenum (P<0.05).　Conclusion　The differentiation of small intestine is fastest at E15.5~E17.5 d, the basic structure of the small intestine with certain digestive and absorptive function is formed during the embryonic period.