Archaeoceratops is one of the oldest genera of horned dinosaurs, which did not differ in large size and spectacular appearance. The archaism of these ornithischias is even emphasized in their name, which means "ancient horned face".

Archaeoceratops, like all ceratopsians, was a herbivore. During the Cretaceous, flowering plants were geographically limited on the landscape, and so it is likely that this dinosaur fed on the predominant plants of the era: ferns, cycads and conifers. This is indicated by the presence of a beak and strong teeth, as well as by the general structure of the jaw. Scientists believe that it would have used its sharp beak to bite off the leaves or needles and chop them up to be swallowed. It is noteworthy that Archaeoceratops is one of the most recently discovered dinosaurs - it was described only in 1997 after a discovery in northern central China.