Abstract: In order to obtain a complex bacteria agent that can be used in the fermentation of corn stalk and improve its quality as silage, two Bacillus amyloliquefaciens strains with high lignocellulose-degrading ability were mixed to make a complex agent whose degradation effect could be studied. The microstructure and degradation products of corn stalk inoculated with the complex bacteria agent were analyzed using FTIR, ¹H-NMR, SEM and GC/MS. Fermentation tests showed that the microbial agent efficiently degraded lignocellulose in corn straw. When the agent was inoculated for 24 days, the degradation rate of lignin, cellulose and hemicellulose reached 48.4%, 30.5% and 41.4% respectively. FTIR and ¹H-NMR spectrum analysis showed that the main linking covalent bonds, such as β-O-4 and β-β linkages between the lignin monomers, the bonds connecting the lignin to cellulose and the carbohydrate bonds in lignocellulose’s molecular structure, were all broken. The complete destruction of plant tissue structure was also observed with electron microscope scanning. GC/MS analysis of low-molecule substances in the fermented corn stalk showed that the lignin was degraded into small molecular aromatic compounds, including amphetamine and phenylpropionic acid, monomers produced by the depolymerization of lignin, and benzyl alcohol and benzoic acid esters, which are degradation products of lignin phenyl propane monomers. GC/MS analysis of carbohydrate degradation products showed that the complex bacteria could not only convert cellulose, hemicellulose and other macromolecule carbohydrates into reducing monosaccharides, such as glucose, xylose, mannose and galactose, but that it could also metabolize these monosaccharides into glycol, glycerol and short-chain fatty acids. In conclusion, these results show that the complex bacteria agent effectively degrades lignocellulose and could be widely used to convert corn stalk into high quality forage.