In this work, the electroless copper method with different reductant compositions (NaHSO 3 /Na 2 S 2 O 3 Γ5H 2 O and Na 2 S 2 O 3 Γ5H 2 O) without sensitizing and activating, was used to deposit copper-sulfide deposition on the polyacrylonitrile (PAN) surface for electromagnetic interference (EMI) shielding materials. The weak reductant, NaHSO 3 , in the electroless copper method was used to control the phase of copper-sulfide deposition. The Cu x(xΒΌ1-1.8) S was deposited on the PAN (Cu x S-PAN) by reductant composition (NaHSO 3 /Na 2 S 2 O 3 Γ5H 2 O) and the Cu x(xΒΌ1-1.8) S deposition of Cu x S-PAN possesses three kinds of coppersulfide phases (CuS, Cu 1.75 S and Cu 1.8 S). However, the electroless copper with reductant was only Na 2 S 2 O 3 Γ5H 2 O (without weak reductant, NaHSO 3 ), the hexagonal CuS deposition was plated on the PAN (CuS-PAN) and increased the EMI shielding effectiveness of CuS-PAN composites about 10-15 dB. In this study, the best EMI SE of CuS-PAN and Cu x S-PAN composites were about 27-30 dB and 15-17 dB respectively, as the cupric ion concentration was 0.24 M. The volume resistivity of CuS-PAN composite was about 1000 times lower than that of Cu x S-PAN composite and lowest volume resistivity of CuS-PAN composites was 0.012 X cm, as the cupric ion concentration was 0.24 M. V C 2010