Abstract: The Haihe River basin experienced severe drought and water shortage since the 1980s; furthermore, the evaporative capacity of the natural climate cycle shows a significant downtrend. The long-term change in absolute humidity was studied using historical data from reference stations. The preliminary results indicated that absolute humidity was on the rise in the interdecadal timescale, especially during the field irrigation season in May or June, where the uptrend was more prominent. There was an obvious zooming in atmospheric absolute humidity since the middle of the 1980s and the zooming extended up to about 10%. The reasons for this and the consequences for the climate and environment warranty further study of the important role of water vapor in the weather, climate, and hydrological cycle.