"Chaohusaurus" is a basal ichthyopterygian. It thus shows traits that are typical for the direct ancestors of ichthyosaurs. As a result, basal ichthyosaurs like "Cymbospondylus" and "Mixosaurus" are closer in build to "Chaohusaurus" while later genera like "Ichthyosaurus" have a more derived morphology. "Chaohusaurus" did not have the dolphin-like form of later ichthyosaurs; it had a more lizard-like appearance with an elongated body. These proportions were not caused by a large number of vertebrae, the total of presacrals being about forty, but by an elongated build of each individual vertebra. The head is short, in adults having about the third the length of the trunk, with a narrow pointed beak and large eye-sockets. Its teeth are conspicuously heterodont, differing in shape: those of the upper jaws are pointed though blunt; those of the rear lower jaws are bulbous with a convex profile, a possible adaptation to a durophagous diet, crushing shellfish. The neck is relatively long. "Chaohusaurus" did have flippers, rather than webbed feet. The tail fin is wide-based in side-view and short.