Based on the “yin-yang of the four seasons and the five viscera” theory of TCM, this study systematically observed the effects of seasonal change of winter and summer on the hypothalamus-pituitary gonad axis function and the role of melatonin in this seasonal change, from the representative factors into the seasonal variation of illumination, to explore the scientific connotation of this theory. The content of MT, GnRH, LH, FSH, T in the plasma, hypothalamus, pituitary and testicular tissues of male golden hamster rats were detected, and the content of MR in various tissues were detected. The results showed that the content of GnRH in hypothalamus, LH and FSH in pituitary, T in testicular were characterized by high in summer and low in winter (P<0.01). Content of GnRH and T in plasma was high in summer and low in winter (P<0.01). FSH in plasma was higher in summer, but there was no statistically significant difference (P>0.05). Content of LH in plasma was higher in winter (P<0.05); Content of MT in plasma, the hypothalamus and testis were low in summer and high in winter (P<0.01); the content of MT and MR in the pituitary gland was higher in summer than winter (P<0.01). The content of MR in the hypothalamus and the testes was higher in winter (P<0.01 or P<0.05). Conclusion:The function of hypothalamic-pituitary-gonadal axis is characterized by seasonal changes in winter and summer, and MT may be involved in the regulation of this change, which can affect the secretion of gonadotropin. The timely regulation of reproductive function suggests that there is indeed an adaptive variation law in coordination resonance between the body and the natural season.