Bismuth ferrite, BiFeO3, was an important multiferroic material, which simultaneously exhibited ferroelectric ordering and antiferromagnetic ordering in the bulk form. The solid solutions of Bi0.9Y0.1FeO3 with PbTiO3 were prepared by the conventional solid state reaction. It was clear that in Bi0.9Y0.1FeO3-PbTiO3 solid solution, the structure remined rhobohedral for 85 mole% of Bi0.9Y0.1FeO3, from 80 to 70mole% it were rhobohedral and tetragonal, and below 65 mole%, the structure transformed to tetragonal. The dielectric and ferroelectric properties of the ceramics had been significantly improved by means of ionic substitution of Ti4+ for Fe3+, which reduced the electric conductivity. The dielectric constants of the ceramic samples were enhanced from 84 to 241 and the remnant polarizations were improved from 0.494 to 2.17 μC/cm2.