Abstract—The purpose of this paper is to study in more detail response characteristics by means of correlation and interaction between purging rate and tube length with different parameters to establish proper environment parameters in calibration procedure of the dew point sensor (DPS). The effect of purging rate and tube length condition on the measured dew point temperature and correlation between them were investigated by analyzing variation of measurement results due to various reference dew points with capacitive dew point sensor with aluminum oxide during a time period of over a year. The measurement is carried out to analyze the variation on measured dew point temperatures for sampling dew point sensor (DPS) due to various purging rate from 5 hours to 120 hours and tube length condition from 1000 mm to 6500 mm by using calibrated standard chilled mirror hygrometer. The correlation and interaction between purging rate and tube length condition on the measurement accuracy and reliability were analyzed with measurement results for reference dew point temperatures from -60 ℃ to 10 ℃. The measurement was conducted according to standard calibration procedure of Korea Testing Laboratory which assures suitability and traceable results. It is also based on international standards.