The invention discloses a few-mode time-domain reflectometer, and belongs to the technical field of fiber characteristic measurement. The reflectometer is composed of a signal generation module, an optical path module, a few-mode fiber module to be tested, a detection module and a data collection and processing module; the signal generation module generates a multi-frequency light pulse signal, the multi-frequency light pulse signal is input to the optical path module, a spatial mode is converted in the optical path module, the light signal after conversion is input to the few-mode fiber module to be tested, backward rayleigh scattered light of the few-mode fiber module to be tested is returned to the optical path module for mode separation, the mode separated light signal is input to thedetection module for photoelectric conversion, and the converted signals is input to the data collection and processing module to realize signal collection, processing and display. The reflectometer fills the blank in an online monitor applied to few-mode fibers, and intelligent network monitoring, damage measurement and fault location of the few-mode fibers are realized.