Sr1-x La (x) Zn (x) Fe12-x O-19/poly(vinylpyrrolidone) (PVP) (0.0a parts per thousand currency signxa parts per thousand currency sign0.5) precursor nanofibers were prepared by the sol-gel assisted electrospinning method from starting reagents of metal salts and PVP. Subsequently, the Sr1-x La (x) Zn (x) Fe12-x O-19 nanofibers with diameters of around 100 nm were obtained by calcination of the precursor at 800 to 1000A degrees C for 2 h. The precursor and resultant Sr1-x La (x) Zn (x) Fe12-x O-19 nanofibers were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometer and vibrating sample magnetometer. The grain sizes of Sr0.8La0.2Zn0.2Fe11.8O19 nanofibers are in a nanoscale from 40 to 48 nm corresponding to the calcination temperature from 800 to 1000A degrees C. With La-Zn substitution content increase from 0 to 0.5, the grain size and lattice constants for the Sr1-x La (x) Zn (x) Fe12-x O-19 nanofibers obtained at 900A degrees C show a steady reduction trend. With variations of the ferrite particle size arising from the La-Zn substitution, the nanofiber morphology changes from the necklace-like structure linking by single elongated plate-like particles to the structure building of multi-particles on the nanofiber cross-section. The specific saturation magnetization of Sr1-x La (x) Zn (x) Fe12-x O-19 nanofibers initially increases with the La-Zn content, reaching a maximum value 72 A m(2) kg(-1) at x=0.2, and then decreases with a further La-Zn content increase up to x=0.5, while the coercivity exhibits a continuous reduction from 413 (x=0) to 219 kA m(-1) (x=0.5). The mechanism for the La-Zn substitution and the nanofiber magnetic property are analyzed.