Abstract: The pyrolysis of rice straw and sawdust under microwave irradiation was performed with ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium tetrafluoroborate as catalysts. With microwave heating for 20min, the bio-oil yield from rice straw reached 38% and that from sawdust reached 34%. The effects of microwave heating time, microwave power, and IL dosage on bio-oil yields were discussed. The chemical components in bio-oil were analyzed by gas chromatography-mass spectroscopy technique. The main components in bio-oil are furfural, acetic acid, and 1-hydroxy-2-butanone, and their contents mainly depend on the source of biomass and the type of IL used in pyrolysis.