The microstructure and properties of phosphate bonded Cr2O3£­Al2O3£­ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2O3£­Al2O3£­ZrO2 bricks after secondary treatment in simulation environment was studied. Finally, corrosion resistances of the Cr2O3£­Al2O3£­ZrO2 bricks in air and simulation environment were compared; and microstructure of onª²site used Cr2O3£­Al2O3£­ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the microstructure and properties of the phosphate bonded Cr2O3£­Al2O3£­ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2O3 and Al2O3 therefore, strength of the specimens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the reduction of phosphate and part of Cr2O3, which results in the increasing number and size of the pores, bad interfacial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also reduced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, in reducing atmosphere, the specimens show much worse corrosion resistance than in air.