Abstract: Y-type hexaferrite Ba_0.4Sr_1.6Mg₂Fe₁₂O₂₂ single-phase polycrystalline samples were synthesized by the solid-state reaction method. The crystal structue of Y-type hexaferrite Ba_0.4Sr_1.6Mg₂Fe₁₂O₂₂ was characterized by X-ray diffraction. X-ray diffraction results show the impure phase is M-type hexaferrite when the sintering temperature is 1120 ℃ to 1160 ℃, respectively. The single-phase Y-type hexaferrite Ba_0.4Sr_1.6Mg₂Fe₁₂O₂₂ was prepared when the sintering temperature is 1170 ℃. The microstructure and composition were analyzed with field emission scanning electron microscope and energy dispersive spectrometer, respectively. Y-type hexaferrite Ba_0.4Sr_1.6Mg₂Fe₁₂O₂₂ shows hexagonal morphology with grain size about 3 μm and small cluster. According to the energy spectrum analysis, the composition of the two forms is the same. The magnetic property was characterized by physical property measurement system. Magnetization curves revealed two magnetic transitions at 330 K and 90 K, which corresponded to conical magnetic ordering and spin-glass phase transition. The conical magnetic phase transitio ordering temperature of Ba_0.4Sr_1.6Mg₂Fe₁₂O₂₂ is higher than the room temperature, which provides the possibility of magnetoelectric coupling at room temperature.