Ni0.3Cu0.07Zn0.63Fe2-xLaxO4 ferrites were prepared by solid phase method and sintered at 1,150 ℃ for 6 h.The phase formation,microstructure,and magnetic properties of samples were investigated.With doping of La3+,the samples contain two phases:LaFeO3 and NiCuZn ferrites.Scanning electron microscope (SEM) image shows that La doping constrains the growth of NiCuZn ferrite,which is more uniform.La doping improves magnetic properties of NiCuZn ferrite when x ≤ 0.03.The saturation magnetization (Ms) increases first;when x =0.03,the highest value is 75.35 A.m2.kg-1.The permeability increases to the maximum value with frequency and then decreases with the concentration of La3+ increasing.When x =0.03,the maximum value of real permeability at 1 MHz is 333.5,and the loss angle tangent (tanδ) is not more than 0.02.La doping improves the properties of NiCuZn ferrite,which can be applied to low-frequency filters.