The effect of the additive on the dielectric property of $TiO_2$ containing 0-2.5wt %. $Sb_2O_3$ was investigated as a function of frequency from $5{ imes}10^4$ to $6.3{ imes}10^7$ cps and temperature from 25 to 375$^{circ}C$. The dielectric constant increased with increasing $Sb_2O_3$ concentration from 0.25 to 0.5wt.% It is due to space charge polarization caused by increasing anion vacanices. The dielectric constant decreased for further increase in $Sb_2O_3$ concentration. It can be explained by increasing grain size effect rather than space charge polarization.