Lanzhousaurus lived in the Gansu region of what is now China during the Early Cretaceous (Barremian).

[2] The genus has been described as having "astonishingly huge teeth", among the largest for any herbivorous creature ever, which indicate it was a styracosternan iguanodont.

[3] In their 2020 reassessment of the hadrosauromorph Orthomerus, Madzia, Jagt & Mulder ran phylogenetic analyses of Iguanodontia.

In their analyses, Lanzhousaurus was recovered as a non-hadrosauriform styracosternan member of the Ankylopollexia, similar to the 2005 description by You, Ji & Li.

The results of their phylogenetic analyses are shown in the cladogram below:[4][1] Camptosaurus Cumnoria Uteodon Draconyx Planicoxa Theiophytalia Hippodraco Owenodon Muttaburrasaurus Dakotadon Osmakasaurus Cedrorestes Iguanacolossus Lanzhousaurus Yunganglong Fukuisaurus Siamodon Hypselosaurus Barilium Lurdusaurus Iguanodontidae Hadrosauroidea