文章讨论了谱色测温系统研究中，基于测温坐标系的辐射测温区域的界定问题。以线性发射率模型以及改进的单调发射率模型为基础，通过测温坐标系标尺的考察，分析了不同光谱发射率模型下的辐射测温坐标系所限定的辐射测温有效区域的规律特征；以实际应用中特定的谱色测温仪器为例，给出该仪器适用的辐射测温的理论区域，并用黑体实验进行了验证。

In the research of primary spectrum pyrometry, this paper discussed the definition problem of radiation temperature measurement area based on the measurement coordinates. For the linear spectrum emissivity model and improved monotonic spectrum emissivity model, the characteristics of radiation temperature measurement area restricted by the measurement coordinates were theoretically analyzed, through the investigations of the temperature and emissivity coordinate axes. Choosing the specific primary spectrum pyrometer as an example in applications, the theoretical area of radiation temperature measurement of this pyrometer was given. And it was verified through blackbody experiments. The discussions of this paper will provide the necessary foundation for the theory research development of primary spectrum pyrometry and the realization of technical applications.