Ultrafine ZrO2 suspension with stable high solid loading was prepared, and ZrO2 ceramic materials with uniform structures were fabricated through gelcasting. Zeta potential of the ultrafine ZrO2 suspensions with A-type dispersant, triammonium citrate, and without dispersant was measured. The influencing factors on suspension flowability as the content of dispersant, pH value, solid loading, and milling time were studied in detail. And the optimum premixed solution/initiator (APS)/catalyst (TEMED) ratio for gelcasting was investigated. The results showed that A-type dispersant was suitable for dispersing of ultrafine ZrO2 particles in aqueous premixed solutions; the optimized content of dispersant was 2%~2.5% of ZrO2 volume; ZrO2 suspension displayed a minimum viscosity at pH 10.66; the upper limit of solid loading was 54vol.%; and the appropriate milling time was 12 hours. When premixed solution/initiator (APS)/catalyst (TEMED) ratio was 100/1/0.5, ZrO2 suspension has a better gelcasting behavior.