Three fossils of Beishanlong were found in the early twenty-first century in Northwestern China at the White Ghost Castle site, in the province of Gansu.

The type species is Beishanlong grandis, described and named online in 2009 by a team of Chinese and American paleontologists, and formally published in January 2010 by the same Peter Makovicky, Li Daiqing, Gao Keqin, Matthew Lewin, Gregory Erickson and Mark Norrell.

[1] Beishanlong lived in the late Aptian stage,[2] with its fossils being uncovered in layers of the Xinminpu Group, in the Xiagou Formation.

According to the description, Beishanlong "is one of the largest definitive ornithomimosaurs yet described, though histological analysis shows that the holotype individual was still growing at its death."

[1] In 2014 Yuong-Nam Lee et al. recovered Beishanlong as a member of Deinocheiridae basal to a clade containing Garudimimus and Deinocheirus.