Abstract: Polyaniline-Ni nanocomposites were synthesized by in situ aqueous polymerization of aniline in the presence of Ni. The structure、norphologies、magnetic and electrical properties of samples were characterized by scanning electron microscope (SEM)，X-ray diffraction(XRD)，Fourier transform infrared spectra (FTIR)，four probe method and vibrating sample magnetometer(VSM) techniques.The results indicated that the nanocomposites under applied magnetic field exihibited the hysteresis loops of the ferromagnetic nature at room temperature，Saturation magnetization was 9.44 emu/g. The electrical conductivity was 5×10-3 S/cm.