The invention relates to an emulsified SBS 
polymer modified 
asphalt and preparation method thereof. At present, emulsification and emulsified modified 
asphalt applied to surfacing is hard to produce and not stable in quality, high temperature 
performance improvement is not obvious. The raw materials of the invention are matrix 
asphalt, water, SBS asphalt modifier, compound asphalt emulsifier, emulsification stabilizer and 
hydrochloric acid; firstly the matrix asphalt is heated, added with SBS asphalt modifier and then stirred to be swelled, 
high speed grinding by 
colloid grinder and full dispersion are carried out, and heat preservation growth is carried out to obtain SBS modified asphalt; compound asphalt emulsifier is added into water, emulsification stabilizer smoothened by water in advance is added, and appropriate 
hydrochloric acid is added to adjust pH value, so as to obtain 
liquid soap; and finally the SBS modified asphalt is subject to temperature reduction and then mixed with the 
liquid soap and emulsification dispersion is carried out, thus obtaining emulsified SBS 
polymer modified asphalt. The invention is applicable to coat tacking, coat sealing, surface treatment, 
slurry sealing and 
asphalt pavement recycling, asphalt wet-mixing of 
road construction and cerement 
asphalt mortar layer of passenger special line plate type unballasted track.