The presently-disclosed subject matter relates to an artificial RNA nanostructure molecule and method to treat brain tumor in a subject. More particularly, the presently disclosed subject matter relates to a RNA nanostructure containing a multiple branched RNA nanoparticle, a brain tumor targeting module, and an effective amount of a therapeutic agent. Further, the presently disclosed subject matter relates to a method of using the RNA nanostructure composition to treat brain tumor in a subject having or at risk of having brain tumor.