Structure and function of the androgenic gland in Chinese mitten-handed crab, Eriocheir sinensis, were studied w ith tissue section, histochemistry , electron microscope and culture in vitro techniques from April 1996 to March 1997. A pair of androgenic glands were located on the surface of the subterminal portion of the ejaculatory duct near the base of penis. The cords of the gland tissue consisted of many gland alveoluses. The structure of the gland changed great ly with the testis development cycle. The developmental cytology of the gland cells can be distinct ly devided into three stages: proliferation phase, synthesis phase and secretion phase. The gland secreted in a holocrine fashion. The androgenic gland hormone is composed primarily of protein and lipid as indicated by positive reaction to Ninhydrin- Schiff and phosphomolybdic acid. Spermatogenesis can be accelerated and oocyte development can be inhibited by the androgenic glands when cultured in vitro.