Anshunsaurus is characterized by a long jugal bone in the skull, fused postorbital and postfrontal bones around the eyes, a maxilla that forms part of the margin of the eye socket, a humerus with large crests, and a large fibula.

[4] The type species of Anshunsaurus, A. huangguoshuensis, was named in 1999 from the Ladinian or Carnian age Falang Formation in Guanling County.

The pectoral and pelvic girdles are asymmetrical in this specimen, suggesting that the bones on the left and right sides of the animal did not ossify at the same rate while it was growing.

Both thalattosaurs belong to Askeptosauroidea, a group characterized by their long necks and narrow skulls.

These features suggest that A. huangnihensis is a transitional form between earlier thalattosaurs and the later species of Anshunsaurus.