Abstract: The structure and dielectric properties of La-doped Bi₂O₃-ZnO-Nb₂O₅ ceramics were investigated.The sample exhibits a single cubic pyrochlore phase at La³⁺ substitution ＜0.5.The grain size and density values decrease with the increasing of La³⁺ substitution.The relaxation behavior under low temperature exhibits a regular change with La³⁺ substitution.The dielectric constant of BZN samples decrease and the peak temperature of dielectric relaxation moves towards low temperature with the increasing of La³⁺ substitution.When the substitution content of La³⁺ increase from 0.1 to 0.5,the peak temperature moves from-95℃ to-112℃ at 1MHz,respectively.