Polyaspartic acid (PASP) and polyepoxysuccinic acid (PESA) were proved to be strong biodegradable candidates to replace traditional ceramic dispersant polyacrylic acid (PAA) as evidenced by rheological measurements. At low dosages (0.2 wt%), alumina suspensions with PAA were completely flocculated, while those with PESA as dispersant obtained good dispersion, and exhibited much lower viscosity than those with PASP. With further small addition of citric acid (CA), dispersion of alumina suspensions was greatly enhanced than those with single dispersant PASP or PESA. Combination of PASP/PESA-CA as ceramic dispersant is effective in dispersing aqueous alumina suspensions until high solid loading.