The Chinese water snake has a large head and a small belly, a dark gray-brown back with irregular small black spots, a pale yellow ventral surface with black spots, and a slightly flat tail. The total length is 700mm.

The back of the Chinese water snake is khaki-yellow, scattered with slightly vertical black dots, on both sides The first row of dorsal scales is black, the second and third rows of dorsal scales are white; the ventral surface is yellow, and the front edge of each ventral scale has a black spot. The torso is cylindrical and the tail is short.