Pituitary was one of most complicated endocrine gland, the function of it was diversification. Pituitary could modulate the activities of the body organs and tissues. It was necessary to investigate structure of fish pituitary in order to provide the basis for histological morphology, reproductive biology and pathology. Using improved staining, Mallory and PAS staining method, and transmission electron microscopy technique, the microstructure and the ultrastructure of the pituitary ofResults showed that: the pituitary of the was a solid spherical glands, and was composed of neurohypophysis and adenohypophysis. According to the shape and size of excretive granule contained in nerve fibers, the neurosecretory fibers could be differentiated into A₁, A₂ and B-type. Two types of pituitary cells could be observed in the neurohypophysis, consistsed of three parts: , proximal pars distalis(PPD) and pars intermedia(PI). It could be identified endocrine cells in a. Adrenocorticotrophic (ATCH) cells and prolactin (PRL) cells existed in the RPD, growth hormone (GH) cells, thyrotrophs (TSH) cells and gonadotrophic hormone (GTH) cells could be found in the PPD, only one endocrine cell were observed, it was melanophore-stimulating hormone (MSH) cells. And one non-secretory cell type-stellate cells (SC) could also be seen in a. The sort of gonadotrophic hormone cells and endocrine cell were discussed significantly expanded, foam based, and it relatively had a few secretory granules in the cytoplasm. Since the release of secretion of some GTH , nuclear was smaller, degenerate, or even disassemble, and secretory granules was preternaturally rich in the cytoplasm. There also had many GTH that were not found vacuole, and the edge of cell showed lace-shaped or notch, mitochondria well-developed.