At present, the applications of fiber gratings in high-power fiber lasers mainly include two aspects, be used as cavity mirrors and to suppress nonlinear effects. The development of fiber gratings as cavity mirror was discussed firstly, and then the applications of special structure fiber gratings with nonlinear effects suppression function was focused on. The stimulated Raman scattering and stimulated Brillouin scattering suppression method were introduced based on tilted fiber Bragg grating in detail. And the feasibility of suppressing stimulated Raman scattering by long-period fiber grating was also discussed. Further, a novel method of suppressing self-phase modulation or four-wave mixing by utilizing phase-shifted long-period fiber grating was presented. Finally, a prospect of the applications of fiber gratings in high-power fiber laser was provided. Higher power durability and longer wavelength were the definite development directions. And also considered that the femtosecond laser lithography technology, cascaded fiber grating that can suppress multiple nonlinear effects, and polarization control technology based on special structure fiber gratings will become a new research hotspot.