The single-phase multiferroic Bi5Fe1-xNixTi3O15(BFNT-x,x=0,0.1,0.2,0.3,0.4,and 0.5)ceramics were syn-thesized by a sol-gel auto-combustion method,and their microstructures,ferroelectric,magnetic,and dielectric properties were investigated in detail.All samples belong to layer-perovskited Aurivillius phase containing four perovskite units sandwiched between two Bi-O layers.Ni substitution can not only improve ferroelectricity but also enhance the magnetic properties.The BFNT-0.2 sample shows the largest remnant polarization(2Pr～11.6 μC/cm2)and the highest remnant magnetization(2Mr～0.244 emu/g).The enhancement of the magnetic properties may mainly originate from the spin canting of Fe/Ni-O octahedra via Dzyaloshinskii-Moriya(DM)interaction.In order to explore the influence of valance state of magnetic ions on the properties,the x-ray photoelectron spectroscopy was carried out.Furthermore,structural,ferroelectric,and magnetic transitions were also investigated.