Like other stegosaurians, "Huayangosaurus" was a quadrupedal herbivore with a small skull and a spiked tail. Like its more famous relative, "Stegosaurus", "Huayangosaurus" bore the distinctive double row of plates that characterize all the stegosaurians. These plates rose vertically along its arched back. In "Huayangosaurus", the plates were more spike-like than in "Stegosaurus". Like "Stegosaurus", however, it bore two pairs of long spikes extending horizontally near the end of its tail.