An all fiber-optic temperature sensor utilizing stable temperature dependence of radiation induced attenuation (RIA) in fiber is proposed.The irradiated fiber after sufficie nt annealing is used to make sensing head. The test system of temperature sensor is built up to test temperature change o f irradiated optical fiber after accelerated annealing at 70℃.The model between temperature and RIA is built up.The characteristics of the temperature sensor are analyzed from several aspects,such as measuring range,se nsitivity,linearity and repeatability.The attenuation at 850nm of irradiated Ge/P fiber after sufficie nt annealing exhibits monotonic and remarkable temperature dependence in the range from －40℃ to 60℃.It can be seen that the temperature behavior of RIA shows wavelength dependence by analyzing the temperature behavio r of RIA at 850nm and 1310nm.The temperature sensitivity of Ge/P co-doped fiber a t 850nm is better than that at 1310nm.The temperature sensor based on radiation-induced at tenuation at 850nm is feasible.The developed temperature sensor with 18m irradiated fiber has an aver age value sensibility of 0.0068dB/℃.The maximum absolute error is 1℃,the resolutio n is 0.15℃,the nonlinearity error is ±3.04%,and the repeatability error is 1. 04%.