Abstract: The reactor-core neutron and temperature detector is an integrated detector integrating rhodium self powered neutron detector and thermocouple thermometer. The detector can simultaneously measure the neutron fluence rate of the core and the outlet temperature of the fuel assembly. This paper focuses on the design improvement and process improvement plan in the process of detector development, which would significantly improve its reliability under accident conditions. It is verified through experiments that the improved scheme can meet the requirements of the detector technical specifications.