AbstractBamboo (Phyllostachys edulis) samples pretreated with ionic liquid (ILs)-H2O mixtures were studied concerning their application in the pyrolysis process. [Bmim]Cl-H2O, [Bmim]BF4-H2O, [Bmim]HSO4-H2O, and [Bmim]Ac-H2O mixture systems were used in the pretreatment process. The characteristics of pretreated bamboo were analyzed, as was cellulose extracted from ILs-H2O pretreated bamboo. The enrichment of cellulose (α-cellulose) in pretreated bamboo was achieved. The amount of char resulting from the pyrolysis of the [Bmim]Ac-H2O pretreated sample (20.1 wt%) was lower than the untreated bamboo sample (24.2 wt%) at 900 °C. A greater proportion of the pretreated bamboo samples was converted into gas products and/or liquids. The pretreated cellulose pyrolysis process could proceed more easily than processing untreated samples due to the disordered crystalline cellulose structure and the decrease in molecular weight.