The interfacial polymerization of aniline at aqueous/IL has been conducted. The product was characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, thermal gravimetric analysis (GTA), and electrical conductivity measurement. In this route, both solvents used are environmentally benign and polyaniline (PANI) particles with diameters from about 30–80 nm can be fabricated. We believe that this method can be used to synthesize some other useful polymers.