There are a variety of humidity measurement techniques, and the dewpoint humidity measurement technology has great advantages The instrument designed based on dewpoint humidity measurement technology can achieve higher accuracy in the whole range In this paper, based on the calculation formula of saturated vapor pressure from 〖WTBX〗Guide to Meteorological Instrument Observation Methods〖WTBZ〗, the standard uncertainty of relative humidity under different degrees of standard uncertainty of dew point (frost point) temperature is calculated, combined with the theory of error transfer of uncertainty, to explore the advantages of dewpoint humidity measurement technology in accuracy The results show that the standard uncertainty of relative humidity is larger under low temperature and high humidity in the temperature range of -60 to 60 ℃; when the environment temperature and dew point (frost point) measurement standard uncertainty are 01 ℃, the relative humidity measurement standard uncertainty is less than 20%, which meets the minimum requirements of standard uncertainty of humidity standard in the 〖WTBX〗Guide〖WTBZ〗 〖WTBX〗to Meteorological Observation Methods〖WTBZ〗; when the environment temperature and dew point (frost point) measurement standard uncertainty are 03 ℃ (or 05 ℃) and 01 ℃, relative humidity measurement standard uncertainty is less than 43% (or 70%) It can be seen that in the case of low temperature, the relative humidity measurement standard uncertainty of the dew point instrument has obvious advantages