Lorentz transmission electron microscopy (TEM) is a powerful tool to study the crystal structures and magnetic domain structures in correlation with novel physical properties.Nanometric topological magnetic configurations such as vortices,bubbles,and skyrmions have received enormous attention from the viewpoint of both fundamental science and potential applications in magnetic logic and memory devices,in which understanding the physical properties of magnetic nanodomains is essential.In this review article,several magnetic imaging methods in Lorentz TEM including the Fresnel and Foucault modes,electron holography,and differential phase contrast (DPC) techniques are discussed,where the novel properties of topological magnetic domains are well addressed.In addition,in situ Lorentz TEM demonstrates that the topological domains can be efficiently manipulated by electric currents,magnetic fields,and temperatures,exhibiting novel phenomena under exteal fields,which advances the development of topological nanodomain-based spintronics.