In order to investigate the temporal characteristics of its fluorescence background, spectra of the pore water squeezed from sediment core were obtained. Concentration gradient of SO2-4, which suggests depletion of SO2-4 by sulfate reduction, was observed within the pore water using Raman spectroscopy. Besides, a notable fluorescence background difference in the Raman spectra of the pore water over different exposure duration to air was also observed. The fluorescence spectroscopy analysis of the pore water showed that the fluorescence at 300～350 nm increases gradually over time once the sediment core was recovered. Possible explanations for the results were preliminarily discussed.