The　Ru/CeO2　samples　were　prepared　with　loading　Ru　nanoparticles　onto　three　different　shapes　(nanocubes,　rods,　and　polyhedrons)　of　the　CeO2　surface　and　evaluated　for　catalytic　performances　in　CO2　methanation　under　visible　light　or　not.　It　was　found　that　the　cube-like　Ru/CeO2　sample　(Ru/CeO2-c)　exhibited　a　visible　light-enhanced　catalytic　performance,　but　an　insignificant　photopromoted　activity　occurred　on　rod-　or　polyhedron-like　Ru/CeO2　samples　(Ru/CeO2-r　or　Ru/CeO2-p).　The　detailed　catalytic　mechanism　was　monitored　by　temperature-programmed　reduction,　X-ray　photoelectron　spectroscopy,　and　electron　paramagnetic　resonance.　It　was　proposed　that　the　different　photoassist　activities　of　Ru/CeO2　under　illumination　were　caused　by　the　different　metal-support　interaction　forces.　The　strong　interaction　formed　in　Ru/CeO2-c　could　promote　the　photoexcited　electrons　from　cube-like　CeO2　to　transfer　onto　the　Ru　surface,　which　accelerated　the　generation　of　oxygen　vacancies　in　Ru/CeO2-c.　On　the　contrary,　a　weak　interaction　occurred　on　Ru/CeO2-r　and　Ru/CeO2-p　samples.　In　this　case,　the　photoexcited　electrons　would　hardly　transfer　onto　the　Ru　surface,　and　no　more　oxygen　vacancies　were　generated　on　Ru/CeO2-r　and　Ru/CeO2-p,　resulting　in　a　negligible　photopromoted　activity.