The nanostructure and chemical compositions of Ni-based superalloys are investigated utilizing APT instrument LEAP 4000X Si. The article contains the following four contents: nanostructure of γ''-precipitates, refractory elemental partitioning, coherent γ/γ'' interface and clustering and ordering of atoms. Our results demonstrate that it is possible to yield unique and quantitative high quality information in the study of Ni-based superalloys from APT.