Surface photochemistry processes have attracted increasing interest from both fundamental and application viewpoints. The development of scanning tunneling microscopy (STM) provides us a great opportunity to investigate photo-induced structural transition on surface with a high spatial resolution in real space. The detailed structural information of the organization of photoresponsive molecules in the adlayer is resolved and their structural transition during the photochemical processes is observed. The photo-induced structural and property transitions inspire new application potential of photoresponsive molecules in the field of molecular devices, supramolecular assembly and advanced materials.