The invention discloses an optical fiber characteristic parameter measuring device. The optical fiber characteristic parameter measuring device comprises a laser, two single-mode fibers, two optical fiber collimators, two optical fiber couplers, two beam splitters, two phase plates, a plurality of to-be-measured optical fibers, a rotary Doppler effect generator, and a photoelectric detector. The laser generated by the laser is output by the single-mode optical fibers, and is divided into two ways after collimation by the beam splitters, and one way is coupled with the to-be-measured optical fibers after the modulation of the phase plate, and the output light of the to-be-measured optical fibers and the other way of the laser are used to form a light beam after being modulated into light of a specific mode, and the synthesized light beam is transmitted into the rotary Doppler effect generator to form scattered light, and different frequency shifts occur, and at last, the fundamental mode of the scattered light is filtered and detected by the photoelectric detector, and in addition, by analyzing an energy curve acquired by the photoelectric detector, propagation constants, losses, and other characteristic parameters supported by the optical fibers are analyzed. The optical fiber characteristic parameter measuring device has advantages of easy operation and comprehensive analysis.