Six samples (sample J1—J6) from Jingpo Lake in Heilongjiang province were analyzed by fluorescence and fluorescence excitation-emission matrix regional integration (FIR) to determine the different characteristics of dissolved organic matters (DOM). The results with the traditional method just analyzing the excitation, emission and synchronous fluorescence spectra indicated that DOM molecular condensation degree was highest at sample J4 and sample J5, however, the study with the three-dimensional-excitation emission matrix spectra(3EEMs) method showed that the content of protein-like material was higher in sample J6 than others. In the second method, 3EEMs was divided into five regions, among which Region Ⅰ, Region Ⅱ, and Region Ⅳ were related to protein-like material, Region Ⅲ was related to fulvic acid-like material, Region Ⅴ was related to humic acid-like organics, and then these regions were integrated named as AⅠ, AⅡ, AⅢ, AⅣ and AⅤ. The integration results showed that the volume of AⅤ occupied the largest proportion of the DOM region integration from all samples, and it exhibited the most prominent both in sample J4 and sample J5, while it’s opposite in sample J6. Integral ratio, which means humic acid-like region(AⅢ, AⅤ) divided by protein-like region(AⅠ, AⅡ, AⅣ), showed that the value of J4(4.94) was close to J5(5.18), J1(3.52) was close to J2(3.66), and the minimum value appeared in J6(2.11). From the above analysis, the DOM humification degree could be confirmed as follows: J4, J5> J1, J2> J3> J6.