A SBS modified emulsified asphalt was prepared by using linear SBS latex, and the performance of emulsified asphalt was analyzed. Experiments set to test how emulsifier types, amounts of emulsifier, usage of line⁃type SBS latex and preparation technology affect the performance of modified asphalt emulsion. The morphology of modified asphalt emulsion has also been studies by using scanning electron microscope. The experiment results showed that when emulsifier was OP⁃10, usage of emulsifier was 2.0%, amount of line⁃type SBS latex was 4.0%, the shearing rate was 3 000~4 000 r/min, the shearing time was 30 min, the evaporation residue of modified asphalt emulsion was 65.5%, storage stability was 0.43% (1 d) and 2.15%(5 d), penetration was 65 mm and the softening point was 55.7 ℃, which matches the technical requirements of the road modified emulsified asphalt. SBS is also dispersed uniformly in emulsified asphalt.