Micromaching by using femtosecond laser has been developing rapidly. This paper introduces the main developments in the last ten years on the formation mechanisms of periodic ripples in metals, semiconductors, and dielectrics induced by femtosecond lasers. By combining the methods of multi-beam interferences with the self-organized periodic nanostructures, two-dimensional periodic complex nanostructures can be fabricated on the surface of semiconductors. Compared with that of plane surface, the photoluminescence of nanostructures increases greatly.