煤中碳含量的测定对研究煤的分类有着重要的意义，通过碳含量的测定对煤质质量的判定有着重要的作用，碳含量的检测通常使用三节炉法，该方法简便、成熟，但是试验过程中影响因素却比较多，本次研究就对三节炉法测定碳含量进行不确定度评价，以测得值与真实值可能存在的差异大小，同时也可对提高试验的准确性和精密度进行有效指导。本试验选用低阶煤作为样品进行检测，通过分析影响因素确定不确定度评定的来源，经过多次测量，测得的碳含量结果是67.84%时，以常规选择不确定度来源进行分析，扩展不确定度U= 0.005 42%，吸收管的增重称量为主要影响因素；当将气体流速和环境湿度以黑箱模型加入计算时，扩展不确定度为0.029%，经分析，环境湿度为主要影响因素。

The determination of carbon content in coal is of great significance to the study of coal classification. The determination of carbon content plays an important role in the determination of coal quality. The detection of carbon content usually uses the three-section furnace method. This method is simple and mature, but there are many influencing factors in the test process. In this study, the uncertainty of carbon content determined by the three-section furnace method was evaluated to determine the possible difference between the measured value and the real value. It can also effectively guide the improvement of the accuracy and precision of the test. In this experiment, low-rank coal was selected as a sample for testing. The source of uncertainty evaluation was determined by analyzing the influencing factors. After multiple measurements, the measured carbon content was 67.84%. When the source of uncertainty was analyzed by conventional selection, the expanded uncertainty U=0.00542%, the weight gain of the absorption tube was the main influencing factor ; when the gas flow rate and environmental humidity are added to the black box model, the expanded uncertainty is 0.029%. After analysis, environmental humidity is the main influencing factor.