Well-aligned and uniform Co0.8Zn0.2Fe2O4 nanofibers (NFs) are prepared by electrospinning via sol-gel and subsequent heat treatment. Each of the as-spun NFs has a diameter of about 300 nm and a smooth surface morphology. The scanning electron microscope (SEM) image shows that the diameter decreases to 70 nm after the Co0.8Zn0.2Fe2O4 NF has been annealed at 650 ffi C for 3 h. The structure and chemical of Co0.8Zn0.2Fe2O4 NF are investigated by Xray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS), respectively. Single phase cubic spinel structure, Co0.8Zn0.2Fe2O4 NF, is successfully obtained after having been calcined at 550 ffi C in air for 3 h, and a reduced lattice constant of the Co0.8Zn0.2Fe2O4 NF provides the evidence of effective Zn2 + substitution. The magnetic measurements show that the substitution of Zn2 + for Co2 +, i. e., the introduction of non-magnetic Zn2 + ions into A sites, can increase the saturation magnetization (Ms) and reduce the coercivity (Hc). The obtained Hc results of different samples reveal that the critical single-domain size of the Co0.8Zn0.2Fe2O4 NF is approximately 44 nm. By doping Zn2 + with different concentrations, the morphologies of Co1-xZnxFe2O4 (0 <= x <= 0.5) NFs do not show obvious changes. For magnetic properties, the Ms increases and Hc decreases monotonically, respectively.