Abstract: Taking bamboo sawdust as the raw material, various solid acids were used to catalyze the biomass liquefaction, and the effects of different acid strength, acid amounts and acid types on the liquefaction rates and component contents of bamboo sawdust were studied. The acid strength, acid amounts and the surface acid properties of the solid acid were analyzed by ammonia temperature program desorption method (NH3-TPD) and pyridine infrared spectroscopy (Py-IR). The results showed that the more strong acid sites corresponding to the solid acid, the higher liquefaction rate of bamboo sawdust. When the solid acid was used to catalyze the liquefaction of bamboo sawdust, lignin and hemicellulose began to liquefy at first, and the cellulose content in the solid residue increased. When the liquefaction of bamboo sawdust was catalyzed with solid phosphoric acid (SPA) with the most strong acid sites (1.21 mmol·g^-1), , the liquefaction rate of bamboo sawdust could reach 62.0%, and the glucan content in the residue after liquefaction could reach 83.38%.