The intrinsic high magnetocrystalline anisotropy equivalent field can help the hexaferrites break through Snoek's limit and increase the resonance frequency. This is advantageous for microwave absorption applications in the mid to low-frequency range of gigahertz. In this study, we prepared Z-type Ba3Co1.6−xZnxCu0.4Fe24O41 hexaferrites using the sol-gel auto-combustion method. By changing the ratio of Co and Zn ions, the magnetocrystalline anisotropy of ferrite is further manipulated, resulting in significant changes in their magnetic resonance frequency and intensity. Ba3Zn1.6Cu0.4Fe24O41 with high-frequency resonance achieved the lowest reflectivity of −72.18 dB at 15.56 GHz, while Ba3Co1.5Zn0.1Cu0.4Fe24O41 with stronger loss obtained the widest bandwidth of 4.93 GHz (6.14–11.07). Additionally, we investigated surface wave suppression properties previously overlooked. Ba3Co1.5Zn0.1Cu0.4Fe24O41 can achieve a larger attenuation at low frequency under low thickness, which has an excellent effect on reducing backscattering. This work provides a useful reference for the preparation and application of high-performance magnetic-loss materials.