Co3O4-Ni0.6Zn0.4Fe2O4 composites with different Co3O4 content have been synthesized by the hydrothermal combining with sal-gel methods. Exchange bias and significant coercivity enhancement have been observed around and below Neel temperature, T-N, of Co3O4 at certain Co3O4 content. Interestingly, the exchange anisotropy does not vanish at a much higher temperature of 200 K above T-N. The exchange anisotropy behaves complexly with Co3O4 content at different temperatures, which suggest that exchange anisotropy are affected by not only the coupling between ferrimagnetic and antiferromagnetic phases but also the interfacial magnetic states. (C) 2013 Elsevier Ltd. All rights reserved.