Abstract: Biomass energy has expanded rapidly in recent years, and more and more attention has been paid to the pyrolysis of biomass. In this study, rice hull was chosen as the raw material for microwave pyrolysis to produce bio-oil，in order to take full advantage of the biomass waste and to provide a new way of obtaining renewable energy. The results showed that the optimum conditions for the microwave pyrolysis were as follow: pyrolysis temperature was 600℃, microwave power was 2 kW, addition of microwave absorbent was 3%, reaction time was 5 min. Therefore rice hull was suitable for the preparation of bio-oil by microwave pyrolysis process.