An isolated doughnut-like molybdenum(V) cobalto-phosphate cluster with the formula (C11NH10)2{[Co(H2O)6]@[H29Co16Mo16(H2O)16(PO4)24O36]}(H2PO4)·25H2O has been successfully synthesized by a hydrothermal method. Single crystal X ray diffraction analysis shows that four {Co4O60} tetramers and eight {Mo2O10} dimers are linked by oxygen atoms and phosphate groups to construct a doughnut-type structure for [Co@{Co16Mo16}], in which one [CoII(H2O)6]2+ octahedron is enclosed. More importantly, [Co@{Co16Mo16}] exhibits promising photocatalytic performance for CO2 reduction with the CO formation rate of 6764.3 μmol g-1 h-1 and the selectivity of 96.89%. In addition, the cycling test indicated that [Co@{Co16Mo16}] can be reused for at least four cycles without significant loss of catalytic activity. The result of this work may provide new insight for the synthesis of highly efficient POM-based photocatalysts for CO2 reduction.