The sp2 hybridized carbon allotropes such as fullerenes and graphene are scientifically and technologically significant because of their unique elastic and electronic properties. These properties make them useful in a wide variety of applications. Recently, experimentalists have synthesized sp-sp2 hybridized carbon tubular arrays of two-dimensional carbon films, referred to as graphdiyne. To explore the possible existence of an sp-sp2 hybridized one-dimensional carbon allotrope, we investigate graphdiyne nanotubes' structural and electronic properties using dispersion-corrected density functional theory calculations. Graphdiyne nanotubes display unique porous characteristics and remarkable stability, which may promote them as a novel class of carbon materials.