The structure of cellulolytic enzyme lignin (CEL) prepared from three bamboo species (Neosinocalamus affinis,Bambusa lapidea, andDendrocalamus brandisii) has been characterized by different analytical methods. The chemical composition analysis revealed a higher lignin content, up to 32.6% ofB. lapideaas compared to that ofN. affinis(20.7%) andD. brandisii(23.8%). The results indicated that bamboo lignin was ap-hydroxyphenyl-guaiacyl-syringyl (H-G-S) lignin associated withp-coumarates and ferulates. Advanced NMR analyses displayed that the isolated CELs were extensively acylated at the γ-carbon of the lignin side chain (with either acetate and/orp-coumarate groups). Moreover, a predominance of S over G lignin moieties was found in CELs ofN. affinisandB. lapidea, with the lowest S/G ratio observed inD. brandisiilignin. Catalytic hydrogenolysis of lignin demonstrated that 4-propyl-substituted syringol/guaiacol and propanol guaiacol/syringol derived from β-O-4′ moieties, and methyl coumarate/ferulate derived from hydroxycinnamic units were identified as the six major monomeric products. We anticipate that the insights of this work could shed light on the sufficient understanding of lignin, which could open a new avenue to facilitate the efficient utilization of bamboo.