Fe(NO3)3·9H2O and Sr(NO3)2 were used as starting materials to form sol in the water solvent and then the sol formed gel on the surface of the absorbent cotton template. The strontium ferrite micropipe was prepared by calcining the gel. The SrLaxFe12-xO19(x=0-0.3) micropipe sample with excellent magnetic properties was obtained by doping La. The microstructure, morphology and magnetic properties of the sample were characterized by XRD, SEM and VSM. Results show that the morphology of the La-doped strontium ferrite remained the organism morphology of cotton fiber on the whole. The external diameter of the micropipe was between 8 μm and 13 μm, and the wall thickness was between 0.5 μm and 1 μm. When the calcining temperature was constant, the coercive force and the saturation magnetization of the sample increased first, and then decreased with the increase of x value. But the change of the saturation magnetization lagged the coercive force