Abstract: Ceramics (Bi_{1. 5-x}Y_xZn_{0. 5}) (Zn_{0. 5}Nb_{1. 5}) O₇(BYZN, 0≤x≤0. 2mol) was prepared by a solid phase reaction. The structure and dielectric properties of Y³⁺ doped on A site were studied by X-ray diffraction method and scanning electron microscope and Agilent 4284A testing analyzer. The samples exhibited a single cubic pyrochlore phase when Y³⁺ substitution x < 0. 15 mol, and the second phase appeared when X³⁺ content increased. The grain size and dielectric properties of BYZN samples changed regularly with the increasing of doping substitution. The peak temperature of dielectric relaxtion moved from -117 ℃ to -108 ℃ at 1MHz and the εr-T peak was decreased and broaden when substitution x≤0. 15 mol.