The invention provides a relaying and amplification module for an optical fiber sensor. Signal light of a signal wavelength of 1550nm is inputted into a Raman scattering distributed optical fiber sensor (DTS); a multi-mode optical fiber is adopted; the input light enters an optoelectronic isolator and is inputted into an erbium-doped optical fiber amplifier; the erbium-doped optical fiber amplifier amplifies the signal light and inputs the amplified signal light to a wavelength division multiplexer; the wavelength division multiplexer further transmits the amplified light signals to an extended Raman distributed optical fiber sensor (DTS); prolonged sensing optical fiber returned light signals are also received by the wavelength division multiplexer; the returned light signals are transmitted to an optoelectronic isolator through the optical fiber; a single-mode optical fiber transmits the returned light signals to a controller; and photoelectric conversion is performed, and then the prolonged optical fiber sensor signals are extracted. The relaying and amplification module for the optical fiber sensor of the invention is installed at the tail end of the distributed optical fiber sensor to amplify the signals in the optical fiber, realize the bidirectional gain of the light signals, and prolong the detection distance of the optical fiber sensor, thereby reducing equipment costs.