It was demonstrated that gel-free styrene-butadiene-styrene triblock copolymer (SBS) latex with a molecular weight about 90 kg/mol and styrene composition about 34% could be synthesized by reversible addition-fragmentation chain transfer miniemulsion polymerization. The resulted SBS might be an excellent thermoplastic elastomer as indicated by its mechanical properties with ultimate tensile strength of 16 MPa and about 800% elongation at break.