Paul Sereno and Zhao went on a dinosaur fossil hunt in 2005 to Tibet to look for a site that Zhao had found 27 years prior. Before this hunt, in 2001, they had been engaged in a dig in the Gobi Desert. This involved a rock quarry that led them to finding 25 skeletons of the species Sinornithomimus dongi.[2][3]
In 2008, Zhao was involved in and in charge of a dig in Zhucheng that consisted of digging out a "980 ft-long pit". The site has unearthed more than 7,600 fossils through Xijin's work.[4][5] It is believed to be the largest such site in the world. The majority of the fossils found appeared to be from the Late Cretaceous period.[6]