The stable precursor slurry of indium-tin-oxide (ITO) was prepared using metal In and crystalloid tin tetrachloride as raw materials by adding different additives. The effect of dispersants on the stability of ITO precursor slurry was studied by Zeta potential value, TEM and sediment. The influences of pH value and dispersant content on stability of the slurry were investigated. And the effects of the different dispersant and their dispersing mechanism on the stability of the slurry were also investigated. The results show that a higher electrostatic effect could be obtained by adjusting pH value of medium and adding ionic dispersant. Based on the above mentioned, non-ionic surfactants (PEG, PVP) were added, resulting in creating a steric hindered effect among particles, which prevented the agglomeration of the particles so as to obtain a high dispersed and steady slurry. The particle sizes of the slurry were about 10~20 nm. The following finding can be drawn from the experiment that the optimum contents of dispersants are PEG 10% and monoethanolamine 2.5% (mass fraction).