Alkali lignin, an important source of industrial lignin, can be used for the preparation of aromatic components in biofuels by retaining the aromatic ring structure in it through hydrothermal liquefaction technology. The temperature during the reaction prcess has a great influence on the bio-oil yield and components, focusing on the influence of reaction temperature on the oil yield and aromatics yield during the preparation of bio-oil by hydrothemal liquefaction of alkali lignin catalyzed by Mo/Al2O3. The results of the study showed that the oil yield inereased and then decreased with increasing temperature, and the highest oil yield was obtained at 280 ℃. The O/C ratio of the bio-oil decreased continuously with the inerease of temperature to a minimum of 0.22, while the H/C ratio inereased continuously to a maximum of 1.14, and the high calorific value increased continuously to a maximum of 30.41 MJ/kg, which promoted the improvement of the fuel properties of the bio-oil with the increase of temperature. However, the temperature increase was not favorable to the enrichment of bio-oil components to aromatics, the higher the temperature, the lower the relative content of aromatic components in bio-oil and the higher the content of phenolic compounds. The relative content of aromatics reached the maximum value of 34.1% at 260℃ with the addition of 15% Mo/Al2O3, at which time the selectivity to toluene in the aromatics product was as high as 97.7%, and the enrichment of aromatics product was the best.