Due to the ability of local control of light by breaking through the limit of light diffraction, nanostrucrures with localized surface plasmon resonance (LSPR) have gained plenty of attention from the photonic community since its origin. LSPR has played important roles ranging from localized field enhancement effects to the realization of metamaterials. This paper briefly summarizes ultrafast nonlinear optics of nanostructures with LSPR and its applications, with an emphasis on saturable absorption effect of unconventional surface plasmon nanomaterials and their applications in ultrafast lasers. Finally, a prospect for its potential developments is given.