Hydrothermal humification expertise supplies a novel route for the preparation of synthetic humic substances (A-HA), whereas, the mechanism of hydrothermal humification response remains to be wanted to deeply explored. On this research, corn straw is chosen as uncooked materials to conduct hydrothermal humification kinetics experiments, and characterization methods corresponding to ultra-performance liquid chromatography, nuclear magnetic resonance spectroscopy, and Fourier-transform ion cyclotron resonance mass spectrometry is carried out to watch the intermediate merchandise for dedication of the formation mechanism. As noticed, fast dissociation of the lignocellulose can happen in alkaline surroundings, in the meantime, cellulose and hemicellulose have been hydrolyzed into glucose and xylose, additional dehydrated to kind 5 – hydroxy furfural and furfural, then rehydrated to synthesize levulinic acid and different small molecule acids. Then these as-formed small precursors additionally mix lignin fragments to polymerize for formation of fulvic acids, humic acids and even humin. As well as, we additionally use the bought lignin and cellulose as mannequin species for preparation of A-HA to be able to examine the impact of uncooked materials composition on A-HA construction. The proposed mechanism of hydrothermal humification is of nice significance for the design, synthesis and utility of A-HA in sustainable agriculture.