Ultrastructure of the spermatozoa of longdong Stream salamander Batrachuperus longdongensis was studied by both transmission and scanning electron microscopy.  The structural features of spermatozoa in Hynobiidae and Batrachuperus, and the relationship between the evolution of sperm and reproductive evolution in urodeles were discussed. The results show that: 1. the spermatozoa of B. longdongensis share synapomorphy with Hynobiidae, e.g. the clover-shaped acrosome without acrosomal barb, absence  of  mitochondrion in the tail and cylindric axial fibre;  2. the size and structure of nuclear ridge of B. longdongensis differ from other species of Hynobiidae and other families of Urodela significantly, it suggests that the nuclear ridge has specific or generic-specific characteristics in salamanders and newts. Comparative analyses of sperm structures among the tailed amphibians (Urodela)  indicates that: 1.the feature evolution of sperm in urodeles is related to the differentiation of their fertilization modes; 2 the characteristics of  the sperm structure support for  the Cryptobranchoidea monophyly [Acta Zoologica Sinica 51(4):703 –709, 2005].