EMI (Electromagnetic Interference) shielding apeara lot of attention of that electronic devices are being used more widely and reports design progress for shielding..The EMI of PPy/Carbon black synthesized   different weight  (0,1,3,5 wt.%) of C.B  using chemical oxidation method at (3-7)°C and charactrized with  X-ray diffraction , Fourier transformation , Field Emission scanning electron microscopy , Electrical conductivity, high Electromagnetic Shielding Effectiveness (SE) in a frequency range of  5.85- 8.2GHz(C-band), 8.20-12.40GHz (x-band),and thermal analyzed using differential thermal analysis(TGA-DSC). FTIR reveal the required functional groups that should be present in all nanocomposites. The dispersion and  formed a network of conductive phases  that composites had a rough surface and a porous structure of the carbon black particles, according to FESEM results. The PPy  /C.B with the A.C conductivity  (3.04*10^-3 )S/ cm exhibited shielding efficiency SE   in (C-band ) at( -33dB)  is highly dependent on carbon black  and thickness 1.5 mm  , with the maximum SE attenuation recorded at 5wt% of carbon black  being (-36dB )at 12 GHz. Also in( X-band )  that SE attenuation  recorded being at 8GHz . All PPy/C.B  nanocomposites exhibit decreasing dielectric properties (ɛ´, ɛ´´, tan δ) with increasing frequency .These nanocomposites demonstrate effective EMI shielding and can be used in various applications such as molecular electronics and microwave absorption materials. Test of TGA-DSC show that  exothermic reactions with the dominating weight% take place in ( 25-800) °C,  the glass transition temperatures (Tg) at low and high contents of PPy/C.B nanocomposites  between ( 110-160 °C ) . The obtained values of Tg showed complete miscibility of most composites. Thermo-gravimetric analysis showed that the Carbon black in polypyrrole nanocomposites formula has highest thermal stability with improved degradation temperature at 660-669 ⁰C at 5% weight loss.