Leachates were obtained for mineralized domestic waste of two different landfill ages with the laboratory leaching device. With the simulation experiment for groundwater pollution by landfill leachates, 3-dimensional excitation emission matrix(3DEEM) fluorescence spectra of the groundwater samples which were polluted to different extent were analyzed, all these components in DOM were analyzed using fluorescence region integration (FRI) method, in order to screen the characteristic pollution marks and provide the probability of groundwater pollution monitoring. The results show that the EEM of leachate is characterized by a typical fluorescence chromophore loacted at Ex /Em =280 nm/342 nm and Ex /Em =340 nm/420 nm nearby, dominated by kind of fulvic acid of visible range; and the EEMs of groundwater were characterized by two typical fluorescence chromophores loacted at Ex /Em =280 nm/342 nm and Ex /Em =240 nm/446 nm nearby, dominated by kind of protein-like substrance and fulvic acid of ultraviolet range. With the increase in the proportion of leachate, the fluorescence intensity of fulvic acid in visible range (Ex /Em =310 nm/408 nm nearby) increase, and the fluorescence intensity of protein-like substrance decrease. The groundwater pollution of leachate can be detected by analyzing the change of fluorescence intensity in fulvic acid of visible range, fluorescence intensity ratio of Ex /Em =340 nm/420 nm and Ex /Em =280 nm/342 nm or the FRI of Ⅲ region and Ⅵ region.