使用防护热板法测定莫来石试样在各温度下的导热系数，分析了测量不确定度的来源、并根据ISO/IEC 98-3：2008中的基本方法（GUM法）计算了各标准不确定度分量、合成标准不确定度及扩展不确定度，并确定了各分量的影响大小，最后采用蒙特卡洛法（MCM）对测量不确定度的评定结果进行了比较验证。结果表明：在150~500℃莫来石导热系数测定结果的相对扩展不确定度（k=2）小于4%；板平面内温度分布均匀性在各影响因素中占据主导地位，对导热系数测定结果的影响最大；150℃时的评定结果通过MCM验证，可用GUM法来评定莫来石导热系数的测量不确定度。

The thermal conductivity of mullite at the temperature of 150~500℃ was measured by guarded hot plate method, and the uncertainty sources were analyzed. The standard uncertainty components, combined standard uncertainty and expanded uncertainty were evaluated by GUM method which is a basic method for uncertainty evaluation in standard ISO/IEC 98-3:2008, and the influences of each measuring component on the measurement uncertainty were calculated. Additionally, the evaluated uncertainty was verified by Monte Carlo method (MCM). The results show that the relative expanded uncertainty (k=2) of thermal conductivity of the mullite was lower than 4%. The uniformity of temperature distribution in the plate plane dominated and had the greatest influence on the measurement results of thermal conductivity. The evaluation results at 150℃ were verified by MCM, and the results proved that the measurement uncertainty of thermal conductivity of mullite could be evaluated by GUM method.