We have successfully grafted polythiophene on polyethylene (PE) film with a three reactions step: gas phase bromination on PE, yielding PE-Br; substitution reaction of PE-Br with 2-thiophene thiolate anion, following by chemical oxidative polymerization. The polymerization was carried out in a suspension solution of anhydrous FeCl3 in CHCl3, yielding a reddish PE-PT film after dedoping with ethanol. ATR-FTIR shows that the polythiophene (PT) was grafted on PE in the 2,5-position; on the other hand, PT homopolymer shows a small amount of 2,4 coupling. XPS reveals higher intensity of the S2p, including neutral and positive sulfur. SEM image reveals the island of PT on the PE film. AFM analysis found the thickness of the island is in the range of 120–145 nm. The conductivity of these thin films is in the range of 10−6 S/cm.