Sr₂Bi₅FeTi₅O₂₁(SBFTi) ceramic was prepared by sol-gel self method. The dielectric constant-temperatures from room temperature to 500 ℃, AC impedance and AC conductivity of SBFTi ceramic were tested and analyzed. The results showed that SBFTi ceramic exhibit high dielectric constant, good frequency stability and high Curie temperature compared with Sr₂Bi₄Ti₅O₁₈(SBTi) ceramic and it also exhibit characteristics of diffuse ferroelectrics. The electrical structure of SBFTi ceramics was relatively uniform and the macro resistance, which was attributed to the grain show negative coefficient characteristic with temperature. The activation energies for conductivity was 0.6eV and the oxygen vacancy is the main carrier of the SBFTi ceramic at 200~480℃.