A fire-resistant lining structure of a gasifier comprises a high-chromium brick layer, an aluminum-chromium-silicon brick layer and a fiber compressible material layer which are arranged sequentially from the inner wall of the gasifier to a steel case outside the gasifier, wherein an expansion space is formed between the high-chromium brick layer and the aluminum-chromium-silicon brick layer to provide a thermal deformation space for the high-chromium brick layer and the aluminum-chromium-silicon brick layer, and the aluminum-chromium-silicon brick layer, the fiber compressible material layer and the steel case are closely attached to one another. According to the structure, on the premises that the gasifier runs safely and the temperature of the outer surface of the steel case meets the requirement, the effective thickness of a fire-facing surface brick layer is increased, the maintenance frequency of the gasifier is reduced, meanwhile, the reaction volume in the gasifier can be increased substantially, and the productivity of the gasifier can be improved.