Abstract: To solve the temperature measurement problem in the full-scale experimental facility developed by Institute of Nuclear and New Energy Technology, Tsinghua University for the HTR-PM core effective thermal conductivity measurement, the detailed design and structure of the temperature measuring system were presented in this paper. The temperature measuring environment is a graphite pebble zone and the temperature in it can cover the entire temperature range in HTR’s thermal analysis. Based on the structure of the experimental facility and the arrangement of measuring points, sepecially designed non-standard tungsten-rhenium thermocouples were chosen as the front-end sensors, the data acquisition hardware system based on NI PXI platform was set up, and the software system was programmed by combining the producer/consumer mode and queuing mode. The results in the previous scale-down experiments show that the designed temperature measuring system can satisfy the final experiment and lay the foundation for the pebble bed effective thermal conductivity measurement and the promotion of HTR’s economy and safety.