Remote sensing has become a primary tool to identify and classify the wetland vegetation. Recently, more and more hyperspectral remote sensing is applied in wetland researches, in particular, for wetland vegetation classification. Moreover, the in-depth research on the ground spectral characteristics of wetland vegetation is very significant in classifying the remotely sensed images. The Wild Duck Lake, a typical freshwater wetland, was selected as the research area. The reflectance spectra were acquired for the typical wetland plant communities with an ASD FieldSpec HH spectrometer (350-1050 nm). Then, the reflectance spectra were re-sampled to emulate the band configuration of the airborne hyperspectral imagery (OMIS) across the visible to near infrared (NIR) wavelengths. Second-derivative analysis was applied to these transformed spectra in order to identify which spectral bands were the most biological explanative for the differentiation of wetland vegetation in the Wild Duck Lake. The research established seven distinct wavelength domains across the visible to NIR wavelengths that have importance for mapping wetland vegetation in the Wild Duck Lake. The six frequently occurring bands (presumably with enhanced differentiation power) were identified within six of seven spectral domains. Considering the unique spectral pattern of submergent plant species, three additional bands in Zone Ⅵ (810.6 nm, 821.1 nm, 833.0 nm) were identified having special significance. This research ultimately identified nine optimal spectral bands (515.3 nm, 553.1 nm, 626.5 nm, 687.5 nm, 733.9 nm, 810.6 nm, 821.1 nm, 833.0 nm, 966.8 nm) that appeared to contain the majority of the wetland information content of the full spectral resolution, 50-band, hyperspectral signatures. The nine bands can be used to differentiate wetland vegetation types very well. Submergent vegetation had the unique absorption or reflection features at the band 810.6 nm, 821.1 nm, 833.0 nm, which was obviously different from other vegetation covers. The absorption feature at 515.3 nm and reflection feature at 553.1 nm of floating vegetation were more obvious compared with emergent plants, hygrophyte and mesophyte. Floating vegetation, hygrophyte and mesophyte demonstrated more distinct absorption feature at 687.5 nm than the emergent species, while emergent species displayed the clear absorption characteristic at 733.9 nm. Hygrophyte showed evidence of absorption at 626.5 nm. It was found that mesophyte lacked reflectance characteristic at 626.5 nm. However, it exhibited the strong absorption characteristic at 966.8 nm. The result would not only provide a scientific basis for hyperspectral remote sensing image processing and wetland vegetation mapping in the Wild Duck Lake, but also supply reference for identifying and classification of freshwater wetland vegetation applying remote sensing technology.