The composites of polyaniline (PAn) and SBS were made by polymerization of aniline in the presence of SBS, using a direct, one-step in situ emulsion polymerization technique. The polymerization of aniline was carried out in an emulsion comprising water and xylene containing SBS in the presence of dodecylbenzene sulfonic acid, acting both as a surfactant and a dopant for PAn. The composites obtained can be processed by melt method (MP) or solution method (SP). Conductivity of the composites processed by different methods exhibits different percolation thresholds: 10 wt% for MP sample and 7 wt% for SP sample. At the same content of PAn, the conductivity of SP composite is higher than that of MP composite. The relationships between mechanical properties and PAn content, as well as morphological structure of the composites obtained by the two different processing methods were studied. When the PAn content is lower than 12 wt%, the composites behave like a thermoplastic elastomer with high elongation (similar to 600%) and low permanent set (<50%). The conductivity of composite after secondary doping with m-cresol is about two orders of magnitude higher than the original.