<p>Water vapor migration caused by water vapor circulation in unsaturated soil is one of the important factors leading to the increase of nuclear leakage risk from high-level radioactive nuclear waste repositories and the large-scale salinization of agricultural cropland. Therefore, it is of great significance to study the water vapor circulation process in confined unsaturated soil deeply. Jackson et al. indirectly confirmed the effect of temperature gradients on water vapor circulation in confined soil, but direct observational evidence has yet to be obtained so far. Therefore, in this paper, we design a water vapor circulation device equipped with a specialized soil structure for head amplification, which plays a crucial role in observing changes in the water level of the piezometer tube. The experimental results show that the water vapor circulation with multiple dynamic equilibria can be measured by observing the periodic variation of the water level in the piezometer tube in a closed system. Furthermore, we can also reveal the law of water vapor circulation in an open system quantitatively. Utilizing the law, we propose methods for collecting water in shallow deserts and generating electricity through water vapor circulation.</p>