Abstract: The heavy aromatics are important feedstocks to produce light aromatics. The conversion of heavy aromatics to light aromatics includes many reactions such as hydrodealkylation，disproportionation and transalkylation. The advantages and shortcomings of some representative technologies of the conversion of heavy aromatics to light aromatics，such as TAC-9，ATA-11 and Transplus，are analyzed. The key future trends in this field are presented. According to the characteristics of the conversion reaction，the molecular sieves with small particle size and large pore diameter should be chosen as an active ingredient of solid acid catalysts to produce xylene.