Abstract: Light-matter interactions provide rich information about materials, such as their composition, structure, electrical and mechanical properties, interactions, etc. However, the diffraction limit restricts optical spatial resolution to wavelength scale, which seriously restricts optical detection at the nanoscale. In recent years, near-field optical microscopy based on scanning probe technology has been developed to promote optical resolution down to 10 nm by utilizing strong field confinement and enhancement effect of an optical antenna. In this paper we introduce a type of widely used optical super-resolution technology, that is, scattering-type scanning near field optical microscopy, and its representative applications in material and life science.