The describers of Ruyangosaurus assigned it to Andesauridae.
However, Andesauridae is not monophyletic and, as such, is no longer used.

The most comprehensive phylogenetic dataset to include Ruyangosaurus finds it to be in a polytomy with Andesaurus and other basal titanosaurs and near-titanosaur somphospondyls, supporting the original description's assertion of phylogenetic proximity of it and Andesaurus, though not the precise taxonomic assignment.

However, not all phylogenetic analyses have supported its position as a somphospondyl.
A smaller phylogenetic dataset found Ruyangosaurus to be a non-titanosauriform macronarian based on additional material from the type locality.
The describers of Ruyangosaurus assigned it to Andesauridae. However, Andesauridae is not monophyletic and, as such, is no longer used.
The most comprehensive phylogenetic dataset to include Ruyangosaurus finds it to be in a polytomy with Andesaurus and other basal titanosaurs and near-titanosaur somphospondyls, supporting the original description's assertion of phylogenetic proximity of it and Andesaurus, though not the precise taxonomic assignment.
However, not all phylogenetic analyses have supported its position as a somphospondyl. A smaller phylogenetic dataset found Ruyangosaurus to be a non-titanosauriform macronarian based on additional material from the type locality.
Ruyangosaurus