The　YBa2Cu3O7　nano/microsized　single　crystallites　with　spherical　and　rod-like　morphologies　were　fabricated　hydrothermally.　The　catalytic　performance　of　the　materials　was　evaluated　for　methane　combustion.　It　is　shown　that　there　was　a　clear　relationship　between　the　alpha-oxygen　desorption　or　initial　H-2　consumption　rate　and　catalytic　activity.　The　single-crystalline　perovskite-like　cuprate　catalysts　outperformed　the　polycrystalline　counterpart.　The　good　catalytic　performance　of　the　hydrothermally　derived　YBa2Cu3O7　single　crystallites　is　associated　with　more　alpha-oxygen　adspecies,　better　low-temperature　reducibility,　high-quality　single　crystallinity,　and　unique　morphology.