Strontium Bismuth Niobium (SBN) ceramics was prepared successfully using the powders synthesized from molten salt method. The evolution of microstructure with temperature increasing was studied and the influences of abnormal grain growth on dielectric properties were also presented in this paper. The results showed that pure strontium bismuth niobium ceramics without abnormal grain growth could be formed at 1150°C while the density was almost 95% of the theoretical density. Further investigations on dielectric properties indicated although abnormal grain growth did not shift the Curie point obviously, they lowered the dielectric constant corresponding to the Curie point. The dielectric loss was found to change with the frequency remarkably.