Abstract: Healthy chickens were fed with the transformed lactobacillus mixed in water from 0 to 11days of age, then challenged with the 5×10⁴ sporulated oocysts of E. tenella per bird. Pathologic changes were studied to evaluate the level of protection role of transgenic L. lactobacillu with SO7 gene. The results showed that the pathologic changes of transgenic group changed lightest and that the LaS107 transformed with SO7 gene has a good function to defense the E. tenella challenge. These researches make a good foundation for external genes expressed in lactobacillus and create a brand-new way for using genetic lactobacillus in human being and animals.