Abstract: To enhance the application of ground-based microwave radiometers (MWRs) in meteorological operations, this paper first leverages observations from the MWR RPG-HATPRO and CIMEL sun photometers at Xianghe starion to compare their integrated water vapor (IWV) data, thereby assessing the quality of the MWR-derived IWV data. The results indicate good consistency between the two datasets, with a correlation coefficient close to 0.99 and IWV measurement errors generally less than 2 mm, verifying the reliability of the MWR data. Subsequently, six years of MWR IWV data were used to investigate the daily, monthly, and seasonal variations of water vapor at Xianghe starion. The analysis indicates that the daily variation of IWV at Xianghe exhibits a “high value at night and low value during the day,” with the largest diurnal difference observed in summer (1.85 mm) and the smallest in winter (0.34 mm). The monthly and seasonal variations of IWV follow a unimodal distribution, showing high and scattered values in summer and low, concentrated values in winter. In addition, case studies of continuous and stable precipitation events revealed that IWV begins rising 12 h before precipitation, with an increase rate of over 29%. During the early stage of precipitation, IWV increased sharply, with a growth rate exceeding 129%. The duration of precipitation is positively correlated with the increase in IWV, highlighting the potential of IWV observations for forecasting short-term precipitation.