ZrO2 sizing nozzles with a basic formulation were prepared using 45% (by mass, the same hereinafter) (Mg, Y)－PSZ aggregate, 55% (Mg, Y)－PSZ fines and 5% PVA binder. Al2O3－ZrO2 composite powders ( 3%, 6%, 9% and 12%) prepared by sol－gel method were added to replace the equal amount of (Mg, Y)－PSZ fines. Effects of Al2O3－ZrO2 composite powders on physical properties, phase composition and microstructure of the ZrO2 sizing nozzles were studied. The results show that: the performances of the modified sizing nozzles with 3% Al2O3－ZrO2 composite powder are better than those of the nozzles without composite powder used in current production process, and the thermal shock resistance of the former nozzles is six times of that of the latter one.