Abstract: Bursa of Fabriciu is the central immune organ of avian and is also the place for development, differentiation and maturation of B lymphocytes. In sexual maturity, the structure of Avian bursa of Fabriciu was degenerated and was covered by connective tissue with rich vascular and fat. In order to further understand the mechanism of age-related involution of avian bursa of Fabricius, the research progress on histological characteristics, age-related involution and neuroendocrine regulation of avian bursa of Fabricius were reviewed in this paper.