Abstract：Dynamic changes of CD4+、CD8+T-lymphocytes in bursa of Fabricius, caecal mucosa, caecal tonsil, spleen and thymus in chickens inoculated with E. tenella were studied using immunohistochemistry ABC technique. The results were as follows: (1) CD4+T-lymphocytes in caecal mucosa, caecal tonsil, spleen and thymus began to amplify at the 2nd, peaked at the 6th after primary infection with the exception of bursal of Fabricius with a peak at the 8th, then declined slowly. Transient decrease occurred first at the 2nd after secondary infection , then began a slow increase and a lower peak appeared at the 8th , after then declined gradually. (2) CD8+T-lymphocytes in bursa of Fabricius, caecal mucosa, caecal tonsil, spleen and thymus began to amplify at the 2nd, with a peak at the 8th after primary infection, then decreased slowly; Immediate increase appeared and soon peaked highly at the 5th after secondary infection , then a stable decline was observed .