In this paper, the NixZn(1-x)Fe2O4 (x = 0.2, 0.4, 0.5, 0.6, 0.8) ferrite nanofibers were synthesized by electrospinning method. The microstructure, electromagnetic properties and microwave absorption mechanisms were analyzed (in detail). The results indicated that the nanofiber diameter, the saturation magnetization, the coercivity and the electromagnetic properties could be optimized by tuning the Ni2+ content. The Ni0.5Zn0.5Fe2O4 ferrite nanofiber finally performed the excellent microwave absorption properties. The reflection loss was less than -10 dB in the whole X-band frequencies. The analysis of microwave absorption mechanism indicated that the microwave absorption bandwidth was mainly depended on the input impedance matching, the enhanced electromagnetic loss properties ensured that the entering wave could be mostly absorbed, and the frequency appearing the reflection loss peak was determined by the absorber thickness. (C) 2015 Elsevier B.V. All rights reserved.