Abstract： It prone to arise The inverted Vtype cohesive zone is easy to appear in the furnace bosh during the smelting process of blast furnace, and there is a complex flow process of solidliquid two phases. In view of this harsh environment, an online detective temperature sensor based on the onedimensional heat conduction of metal rod is proposed. Temperature probes are embedded in different positions of the sensor, and the mathematical model of the heat conduction process is established. Based on the numerical simulation, the temperature distribution at different positions of the sensor is analyzed, which is validated by the temperature control experiment. The corresponding relation of the hot end temperature and the temperature at the lower temperature zone is obtained, which can realize the purpose of calculating the temperature of the high temperature zone by the low temperature region and overcome the difficulty that the temperature at the high temperature can not be measured directly. Experimental and numerical simulation are in good agreement, the online detective sensor can provide a new method for intelligent and automatic detection of blast furnace.