Abstract: As a renewable energy, biomass has the advantages of low cost, wide distribution and easy availability, and can effectively alleviate energy pressure and reduce environmental pollution. Microwave pyrolysis technology is one of the effective methods for producing fuel oil and high value-added chemicals. Compared with traditional electric heating pyrolysis, microwave heating has the advantages of fast heating, good uniformity, selective heating, energy saving and easy control. This paper focused on the research progress of microwave technology in the preparation of bio-oil by biomass pyrolysis in recent years, and expounded the factors affecting bio-oil yield, including pyrolysis temperature, microwave power, wave absorber, catalyst, raw material pretreatment, retention time, raw material properties and material size. Finally, the mechanism of microwave pyrolysis was analyzed, and the problems, solutions and development prospects of microwave technology in the application of biomass catalytic pyrolysis to bio-oil were summarized and prospected.