Female black-necked turtle: The carapace is short and wide, the plastron is flat without depression in the center, the tail is thin and short, the base of the tail is thin, the cloaca is closer to the rear edge of the plastron, and the two anal shields of the plastron form The notch is shallower and the notch angle is larger.

Male black-necked turtles: The carapace is long and narrow, and the center of the plastron is slightly Inwards, the tail is thick and long, the base of the tail is thick, the cloaca is far from the rear edge of the plastron, and the two anal shields of the plastron have deep nicks and small notch angles.

The adult turtle of the same year, the male turtle is thinner and smaller; the female turtle is round, thick and large.