Abstract: The microstructure and ultrastructure of genita tract mucosa in sow were observed by histological method and electron microscopic technique. Twenty sows of Landrace× Yorkshire two-way crossbred were selected . The tissue structure of oviduct, uterus and vagina mucosa in sow were respectively observed by transmission electron microscopy(SEM) and light microscopy(LM). The results showed that the genital tract mucosa was composed of epithelia, lamina propria and muscularis mucosa. The cilium and microvilli were observed on the simple columnar epithelium in oviduct and uterus. Some lymphocytes were found in the epithelia and lamina propria, and passed through the epithelia and arrived the epithelial surface. The pseudopod of lymphocytoplasm were jutted out. The mitochondria and Golgi complex were rich in the lymphocytoplasm. Lymphocyte aggregation of genital mucosa were formed in the stroma， lymphocytes in cervix mucosa arrived to the epithelial surface, like the phenomenon “lumen excretion” . Our studies revealed that genital mucosa in sow may be the induce site of mucosal immune, since numerous lymphocytes distributed in it.