Abstract: With samples acquired from different temperature zones in a blast furnace (BF),the erosion mechanism of linings was investigated in thermodynamics and micro-mechanism by thermodynamic calculations,SEM and EDS.The results indicate that bricks are penetrable for the steam of K,but Na penetrates in bricks by airflow mixed with Na compounds.Zn has a larger effect on lining erosion in middle and low temperature zones but much less in a high temperature zone.