The invention discloses a fiber-laser-parameter real-time measurement device based on slant fiber gratings. The fiber-laser-parameter real-time measurement device comprises a fiber carved with slant gratings, a first photoelectric detector, a second photoelectric detector, a first polarizer, a second polarizer, a signal processor, a coupling fiber and a spectrograph; the input end of the fiber carved with the slant gratings is welded to the output tail fiber of a to-be-detected laser; lasers transmitted by the fiber can be reflected to the outer side of the fiber by the output face of reflected light of the slant gratings to a certain proportion through the slant gratings in the fiber carved with the slant gratings; characteristics of reflected light of the slant gratings reflected on theouter side of the fiber are detected through the photoelectric detectors and the like, wherein the characteristics comprise power, spectrums and polarization, and various parameters of lasers in the current fiber can be responded. According to the fiber-laser-parameter real-time measurement device based on the slant fiber gratings in the technical scheme, real-time monitoring can be conducted in the working process of a high-power fiber laser, light splitting monitoring is not required to be conducted at the laser output end, and the system structure is simple and practical.