The microstructure, static, and dynamic magnetic properties have been investigated for BaCoZnFe16O27 doped with small amounts of V2O5 from 0 to 1.5 wt %. The results show that the doping of V2O5 can significantly improve the dynamic properties of W-type barium ferrites at microwave frequency. As compared to the undoped sample, the permeabilities μ0′ and μmax″ increase by about 42% and 67%, respectively, for the sample doped with 1.0 wt % of V2O5. Due to the V2O5 doping, perfect hexagonal-plate grains are formed, leading to the decrease in the natural resonance frequency, due to the large demagnetizing effect. The predicted reflection loss shows that the maximum relative bandwidth Wmax=fup/flow reaches 3.9 for attenuation of more than 10 dB in the sample doped with 1.0 wt % of V2O5. This is a good candidate for electromagnetic materials with low reflectivity and broadband at microwave frequency.