Abstract:As the measurement error of mechanical temperature and humidity meter is unavoidable,the evaluation of its measurement uncertainty is an important content of measurement verification.According to JJF 1059.1-2012 Evaluation and Expression of Uncertainty in Measurement,in order to ensure the accuracy and reliability of the measurement data,this paper introduces the general methods and detailed steps of uncertainty evaluation in measurement results of mechanical temperature and humidity meter.With precision dew point meter,LF-300X temperature and humidity test chamber and self-calibration platinum resistance digital thermometer as the standard,and taking WS-1 mechanical temperature and humidity meter as check meter,the evaluation method is described in detail through an example,and the specific evaluation value of extended uncertainty is given out.