The key factors affecting the application of Blackbody Radiator are introduced, including caliber, effective emissivity, probe temperature difference and temperature controlled repeatability. Based on the analysis of the above factors, the corresponding verification methods and improvement measures are put forward in combination with specific examples; the relation between the above four key factors and the three traceability methods of Blackbody Radiator is analyzed, and suggestions on the selection of Blackbody Radiator and the traceability methods are given.