Abstract: Co-gasification of furfural residue （FR） and coal can achieve efficient and clean utilization of furfural residue, but furfural residue with high alkali metal content will accelerate the erosion of gasifier refractory materials. The influence mechanisms of K₂O content in furfural residue, Al₂O₃ content in refractory materials and erosion temperature on the erosion of refractory materials was studied by XRD, SEM-EDS and FactSage thermodynamic calculation software. The research results were showed that, with the increase of FR ration, the flow temperature of co-gasification ash initially increases and then decreases. When the flow temperature descends, the spreading area of slag on refractory materials decreases, but the permeability increases. As the Al₂O₃ content in the corundum brick increases, the spreading area of on corundum brick increases, but the permeability decreases.When the ration of FR is higher than 40%, Al₂O₃ of brick reacts with slag to form low melting phase of kaliophilite（KAlSiO₄）, which destroys the surface densification of the corundum bricks, and this promotes slag infiltration for the decrease of ash flow temperature. When the ration of FR is less than 40%, the high-melting-point minerals of leucite （KAlSi₂O₆） and anorthite （CaAl₂Si₂O₈） were generated, and this increases ash flow temperature and inhibits slag infiltration. The permeability of slag to refractory increases with the increase of temperature. The activation energy （E_a） of the reaction between the slag and corundum refractory material is 25.453 kJ/mol, the reaction enthalpy （ΔH） is 215.388 kJ/mol, and ΔS is −63.1 J/mol, which indicates that the reaction erosion of slag to corundum brick is difficult to carry out, and corundum refractory has strong corrosion resistance.