The pituitary structures and the immune signals of FSHβ and LHβ of the six fish species (the areolate grouper Epinephelus areolatus, blacktip grouper E. fasciatus, red spotted grouper E. akaara, flagtail grouper Cephalopholis urodeta, honeycomb grouper E. merra and white-streaked grouper E. ongus) widely distributed along the coastline of Japan were investigated.The results showed:the gonadal development of areolate grouper, blacktip grouper, red spotted grouper and flagtail grouper was in the immature stage, however the honeycomb grouper and white-streaked grouper in the mature stage. The pituitary structures consisted of neurohypophysis (NH) and adenohypophysis (AH). The AH was further divided into the rostral pars distalis (RPD), the proximal pars distalis (PPD) and the pars intermedia (PI) from left to right. The immune signals of FSHβ and LHβ were detected in the PPD area or in the PPD and PI areas in six species, and the FSHβ signal intensity was stronger than the LHβ signal in six species. These results indicate that, FSHβ may play more important roles than LHβ in the gonadal development of six species when they were around mature stages. Based on the investigation of the six species of groupers along the coastline of Japan, the information of the interrelation between gonadal development and FSHβ and LHβ hormones function was obtained which may provide the basic biological data and theoretical basis for resource conservation and artificial propagation.