Light aromatic hydrocarbons including benzene,toluene and xylene,as important chemical raw materials,have important applications in the fields of dyes,pesticides and medicine. Petroleum resources is scarce but lignite resources is rich in China. Using the selectivity,high efficiency and heating uniformity of microwave heating technology,it is expected that tar rich in light aromatics is obtained by microwave pyrolysis of lignite. In this study,Yunnan lignite was used as raw material,and a single-mode microwave reactor with higher control accuracy of microwave electric field distribution was adopted,to explore the effects of binary catalysis NiFe2O4,NiMoO4 and Fe2(MoO4)3 on electric field distribution,light aromatics content in tar and pyrolysis behavior during microwave pyrolysis from the perspective of microwave electric field distribution. The dielectric parameters of the coal samples were measured by vector network analyzer,and the electric field distribution was simulated. The results show that the addition of binary metal oxides changes the electric field distribution,reduces electric field intensity and effectively increases the coal samples′ ability of absorbing microwaves energy and converting it into thermal energy,which improves the heating rate and final temperature during pyrolysis. The chemical composition of tar and char was analyzed by GC-MS,FT-IR. The results show that the addition of binary metal oxides increases the content of small molecular alkyl groups and · H in the decomposed system effectively by promoting the cracking of macromolecular alkyl and macromolecular aromatic structures and effectively improves the content of light aromatics in tar. After the adding of NiFe2O4,Fe2(MoO4)3 and NiMoO4,the content of light aromatics increases from 21.21% to 44.28% and 37.46% and 43.21%respectively,but the tar yield decreases from 10.28% to 9.76%,6.51% and 9.20% due to the increase of the cracking reaction,and the gas yield increases;in addition,there are d orbital holes in the active center of the transition metal,and by combining with oxygen-containing groups,an R2-OX-R1 (X is a metal active component) structure is formed,which promotes the cracking of the oxygen-containing structure and has a positive effect on reducing the content of oxygen-containing substances in tar.