This paper deals with the effect of controlled light on the morphology and his-tological structure of the testes in stud ganders during normal reproducdive period and nonreproductive period.The results show that there is a significant difference(P<0.01)in morphology and weight of the testes and spermiogenesis in the seimiferous tubules between the ganders illuminated with controlled natural light and the controt ganders during their non-reproductive period,but no significant difference during their early and surge breeding stage of the normal reprodutive periob.The relationships between the light value and the development of avian genital glands are also discussed.The objective of this study is to offer some useful data to the out-of-season production of geese in Guangdong province.