It is one of the longest and largest known hadrosaurids; the composite skeleton of a medium-sized individual mounted at the Geological Institute of China in Beijing measures 14.72 metres (48.3 ft) in length, and the type skull is 1.63 metres (5.3 ft) long. The weight of this genus is estimated at up to 16 tonnes (18 short tons). With a composite mounted skeleton 16.6 meters long (54.5 ft) it is currently the largest known ornithischian and, indeed the largest non-sauropod dinosaur. It had an unusually long tail, presumably to counterbalance the great weight of the body at the animal's hips.
Like all hadrosaurs its beak was toothless, but its jaws were packed with around 1,500 tiny chewing teeth. A large hole near its nostrils may have been covered by a loose flap, which could be inflated to make sounds.
First described in 1973, Shantungosaurus is known from over five incomplete skeletons. Chinese scientist Xing Xu and his colleagues indicate that Shantungosaurus is very similar to and shares many unique characters with Edmontosaurus, forming a Asian node of Edmontosaurus–Shantungosaurus clade, based on the new materials recovered in Shandong. Remains of several individuals, including skull bones, limb bones, and vertebrae, were found in Shandong, China. These specimens were classified in the new genus and species Zhuchengosaurus maximus in 2007. However, further study showed that the supposedly distinct features of Zhuchengosaurus were simply a result of different growth stages.