W-type barium hexaferrite platelets Ba(ZnxCo1-x)2Fe16O27 (0.1 ≤ x ≤ 0.9) were prepared by a chemical coprecipitation route. The results of field-emission scanning electronic microscopy showed that the grains were regular hexagonal platelets with sizes from 0.5 to 1.5 μm. With increasing x, the coercivity decreased, whereas the saturation magnetization increased. Microwave absorption properties were investigated in the frequency range of 8–12 GHz. An optimal reflection loss (-24.8 dB) reached at 10 GHz for x = 0.5 with a thickness of 2 mm. These results indicated that our samples might be a potential candidate for permanent magnets and microwave absorption materials.