Abstract: The pyrolysis and gasification of solid fuels such as coal, biomass, and solid waste are currently hot research topics with promising applications. However, conventional pyrolysis reactors suffer from uneven heat transfer, clogging,and low heat transfer efficiency, leading to high pyrolysis temperatures, reduced pyrolysis yields, and the need for frequent decoking. To address this issue, a technical approach using molten salts as a direct heat transfer medium for thermal conversion is proposed, which can improve heat transfer efficiency, lower pyrolysis temperatures, and maximize the yield of target products.（1） Molten salt pyrolysis, due to its superior heat and mass transfer characteristics, can reduce the activation energy of pyrolysis and inhibit the release of harmful gases during the pyrolysis reaction.Simultaneously, it retains other inorganic substances and metals within the salt, thus effectively addressing issues such as emissions of sulfides, halides, and heavy metals.（2） For different molten salt systems, the mechanisms of chloride and carbonate salts in the pyrolysis of solid fuels are discussed. Compared to chloride salt systems, which are more corrosive, molten carbonate salts not only exhibit better stability and catalytic activity but also catalytically remove heteroatoms from solid fuels in situ.（3） Molten carbonate salts can also be used for the gasification of solid fuels. Among them, the gasification catalytic activity is highest in the three-component mixed carbonate salt system. However, molten salt gasification occurs at lower temperatures, which may lead to an increase in tar content in the gas. The introduction of transition metals such as Ni into molten salts promotes gasification conversion rates, increases syngas yields, and achieves the production of hydrogen-rich synthesis gas.（4） Currently, the recovery and treatment of molten salts mainly involve processes such as salt cooling, water washing precipitation, filtration, and drying. However, further research is needed to explore low-cost recycling and utilization of molten salts after solid fuel pyrolysis and gasification.