Abstract: Accurate measurement of the concentration of dissolved oxygen in liquid lead-bismuth eutectic (LBE) is the premise to achieve oxygen control. A self-developed Bi/Bi₂O₃ oxygen sensor was used to measure oxygen concentration in LBE. The accuracy and stability tests were carried out in stagnant liquid LBE in the condition of oxygen saturation. The accuracy test results show that the change of experimental electromotive force with temperature is consistent with the theoretical curve in the temperature ranging from 340 ℃ to 480 ℃. The maximum absolute error of electromotive force is -2.6 mV. The stability test results show that the absolute error of electromotive force is -1.4 mV within 50 hours at the temperature of 450 ℃ and the fluctuation in this test is 4 mV.