The measuring performance of GE Dew Point Analyzer is studied. By studying the problems encountered in use, operating requirements, such as the choice of probes, the installation place of a probe, gas tightness, and control of flow, are summarized. Many static tests were conducted with the two pressure humidity generator as the standard. The results show that the relative humidity measured by GE Dew Point Analyzer is lower than that by the two pressure humidity generator; for low temperature, the measurement error is larger and more dispersive. As temperature decreases, the sensitivity declines and the repeatability characteristic becomes worse. At -10 ℃, its performance decreases significantly. The findings are of significance for determining the measuring performance and improving the accuracy and reliability of Dew Point Analyzer.