A series of Mn-Zn ferrite nanoparticles with a nominal composition Mn_1-xZn_xFe₂O₄ (0≤x≤1 with steps of 0.2) were synthesized by a template-assisted sol-gel method. The phase identification and magnetic properties of Mn_1-xZn_xFe₂O₄ were measured by XRD and VSM. The effects of Zn content on the structure and magnetic properties of Mn_1-xZn_xFe₂O₄ were studied. It was found that all the Mn_1-xZn_xFe₂O₄ samples with different Zn content exhibited cubic spinel structure in single phase. With the increase of Zn content, the values of the crystal plane spacing d, average crystal size D, saturation magnetization M_s, Curie temperature T_c all exhibited a decreasing trend, while, the coercivity H_c exhibited a first increasing then decreasing trend. For the Mn_0.6Zn_0.4Fe₂O₄samples, the coercivity Hc exhibited the maximum values. The decreasing of M_s was attributed to the Yafet-Kittel canting, the decreasing of T_c was due to the decreasing of anti-ferromagneticScoupling among sublattices, the variation trend of the coercivity H_c can be explained on the basis of the changes of magneto-crystalline anisotropy K₁ of the samples caused by the change of Mn_1-xZn_xFe₂O₄ formula with different Zn content x.