Combined with the annual variations in mass, volume and somatic index of testis, the changes in testicular microstructure during the annual reproductive cycle was observed in snake (Zaocys dhumnades). The results showed that the seasonal variations in mass, volume, somatic index of testis, seminiferous tubule, and seminiferous epithelium were very evident. The spermatogenetic cycle comprised of six stages with significant features and showed a discontinuous type. Its reproductive type belonged to postcopulative, and its testis somatic index was a reliable parameter for determining the spermatogenesis.