Polyaniline (PANI) nanofibers were fabricated through chemical oxidative polymerization at various organic solvent/water interfaces. The products were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). It is found that the morphologies, microstructures and properties of PANI nanofibers depend not only on the nature of organic solvents but also the adding way of aniline monomers and oxidant.