Numerous diseases in ancient earthen cultural relics are relative to water. Free water and absorbed water in earthen cultural relics’ pore structure bring different influences. During the evaporation of water, free water easily evaporates from soil in favor of drying soil. Relatively, the volatilization of absorbed water is slow, leading to salt damage. Therefore, it is the foundation for relic protection to identify free water and absorbed water in earthen relics and study volatilization behavior. The free water and absorbed water have different polarities in chemistry. FE fluorescence substance with double emission peaks is sensitive to the change of chemical polarity and hydrogen bond, used to indicate polarity difference. This paper introduced FE as florescence probe into the stimulated soil samples with different moisture time. By detecting fluorescence characteristic peaks online during water evaporation, the water form and the volatilization behavior of free water and bound water in soil samples were revealed. In the same way, the fluorescence spectra of the stimulated soil samples before and after consolidation were determined to research the effect of consolidation treatment on the volatilization behavior of different forms of water. FE probe has separable double emission peaks, and the excitation wavelength is in the visible region, avoiding soil’s highly absorptive ultraviolet region. The method proposed in this paper can sensitively detect the water form in earthen cultural relics and evaluate the properties in breathability and water resistance for consolidated earthen cultural relics through the volatilization behavior of different forms of water.