Thermocatalytic　nonoxidative　ethane　dehydrogenation(EDH)is　a　promising　strategy　for　ethene　produc-tion　but　suffers　from　intense　energy　consumption　and　poor　catalyst　durability;exploring　technology　that　permits　efficient　EDH　by　solar　energy　remains　a　giant　challenge.Herein,we　present　that　an　oxygen　va-cancy(Ov)-rich　LaVO4(LaV04-Ov)catalyst　is　highly　active　and　stable　for　photocatalytic　EDH,through　a　dynamic　lattice　oxygen(Olatt.)and　Ov　co-mediated　mechanism.Irradiated　by　simulated　sunlight　at　mild　conditions,LaVO4-Ov　effectively　dehydrogenates　undiluted　ethane　to　produce　C2H4　and　CO　with　a　con-version　of　2.3％.By　loading　a　small　amount　of　Pt　cocatalyst,the　evolution　and　selectivity　of　C2H4　are　en-hanced　to　275　μmol　h-1　g-1　and　96.8％.Of　note,LaVO4-Ov　appears　nearly　no　carbon　deposition　after　the　reaction.The　isotope　tracked　reactions　reveal　that　the　consumed　Olatt.recuperates　by　exposing　the　used　catalyst　with　O2,thus　establishing　a　dynamic　cycle　of　Olatt,and　achieving　a　facile　catalyst　regeneration　to　preserve　its　intrinsic　activity.The　refreshed　LaVO4-Ov　exhibits　superior　reusability　and　delivers　a　turnover　number　of　about　305.The　Ov　promotes　photo　absorption,boosts　ethane　adsorption/activation,and　accel-erates　charge　separation/transfer,thus　improving　the　photocatalytic　efficiency.The　possible　photocatalytic　EDH　mechanism　is　proposed,considering　the　key　intermediates　predicted　by　density　functional　theory(DFT)and　monitored　by　in-situ　diffuse　reflectance　infrared　Fourier　transform　spectroscopy(DRIFTS).