In order to clone and identify differentially expressed genes in the sporogony stage of Eimeria tenella，the cDNAs from unsporulated oocysts and sporulated oocysts of E. tenella were used as driver，respectively，the cDNAs from sporozoites of E. tenella was used tester，Two subtractive cDNA libraries of sporozoites were constructed by using the technique of suppression subtractive hybridization (SSH). the cDNAs from unsporulated oocysts was used driver，the cDNAs from sporulated oocysts was used tester，one subtractive cDNA library of sporulated oocysts was constructed. PCR amplification revealed that the two subtractive cDNA libraries of sporozoites and one subtractive cDNA library of sporulated oocysts contained approximated 96%，96% and 98% recombinant clones，respectively. Fifty positive clones were sequenced and analyzed in GenBank with Blast search from three subtractive cDNA libraries，respectively，thirteen unique sequences were found from the subtractive cDNA library of sporulated oocysts，eight ESTs shared significant identity with previously described. A total of forty unique sequences were obtained from the two subtractive cDNA libraries，nine ESTs shared significant identity with previously described，the other sequences represent novel genes of E. tenella with no significant homology to the proteins in Genbank. These results have provided the foundation for cloning new genes of E. tenella and further studying new approaches to control coccidiosis.