Abstract: Lignin is a complex three-dimensional amorphous natural aromatic polymer with great poten⁃tial to be converted into biofuels as an alternative to traditional fossil fuels. Pyrolysis technology hasbeen proven to be as an effective pathway for converting lignin into high-value chemicals. However,there are challenges such as low product selectivity and poor product stability in the direct pyrolysisprocess, which limit the efficient conversion and economic viability of lignin-based conversion. Cur⁃rently, catalytic fast pyrolysis technology is regarded as a useful technology in overcoming these chal⁃lenges. This paper extensively elaborates on the intricate structure of lignin by introducing its basicstructural units and the multitude of linkage patterns it encompasses. Furthermore, it reviews theprimary sourcesanddiverseclassificationsoflignin.Subsequently,basedonthepyrolysischaracteristics of lignin, the key stages of its pyrolysis process, including the initial, primary, and car⁃bonization stages, are extensively discussed. Due to the unsatisfactory quality of the direct pyrolysisproducts, this paper also explores the necessity of catalytic fast pyrolysis and provides a comprehensiveintroduction and overview of commonly used catalysts. Finally, the paper proposes the future develop⁃ment directions of lignin catalytic fast pyrolysis in terms of depolymerization and value addition.