Two kinds of high chromia bricks with and without phosphate as gasifier linings were postmortem analyzed during their whole service life. The effect of phosphate on the microstructure and phase composition of refractory sections was analyzed. The dense phosphate enrichment layer was observed between the slag penetration layer and the virgin layer, which was considered to reduce the damage of gasifier lining caused by spalling. Phosphate could decompose and migrate slowly under suitable temperature gradient existing in the bricks in service, which would result in the densification of the microstructure earlier than slag penetration. The phosphate in high chromia bricks reduced frequency of spalling due to penetration, which would lead to the lower early wear rate and longer lifetime.