Atomically precise metal nanoclusters, especially the metal nanoclusters with an exotic core structure, have given rise to a great deal of interest in catalysis, attributing to their well-defined structures at the atomic level and consequently unique electronic properties. Herein, the catalytic performances of three gold nanoclusters, such as Au38S2(S-Adm)20 with a body-centered cubic (bcc) kernel structure, Au30(S-Adm)18 with a hexagonal close-packed (hcp) core structure, and Au21(S-Adm)15 with a face-centered cubic (fcc) kernel structure, were attempted for the CO2 cycloaddition with epoxides toward cyclic carbonates. Due to the excess positive charge with a strong Lewis acidity and large chemical adsorption capacity, the bcc-Au38S2(S-Adm)20 nanocluster outperformed the hcp-Au30(S-Adm)18 and fcc-Au21(S-Adm)15 nanoclusters. Additionally, the synergistic effect between the gold nanocluster and co-catalyst played a crucial role in CO2 cycloaddition.