In order to improve the detection accuracy, detection dose range and the number of monitoring points of radiation sensing technology, the optical time domain reflectometer(OTDR) technology is used to observe the radiation induced attenua-tion(RIA) effect of single-mode optical fiber, so as to realize the feasibility of distributed radiation sensing application. The linear relationship between radiation dose and RIA of single-mode fiber is established by calculating the attenuation slope of optical power in OTDR curve. Using single-mode fiber with suitable RIA effect is expected to realize long-distance distributed radiation dose monitoring with high spatial resolution.