The analysis of the literature on the spectral methods of lignins study was carried out. The most suitable spectral methods for elucidating the structural features of soluble organosolv lignins were selected. The possibilities of FTIR, ¹Н NMR, ¹³С NMR and 2D HSQC NMR methods were demonstrated on the example of studying the structure of ethanollignins obtained from fir and aspen wood. It was established that fir and aspen lignins are G type and GS type lignins, respectively. The HSQC spectra analysis demonstrated a presence of β–O–4′, β–β′, β–5′ linkages in the ethanollignins. It was found that β–O–4′ linkages in ethanollignins from fir and aspen were partially acylated with ethoxy groups in the α-position.