The invention discloses a dication and dianion type asphalt emulsifier, and belongs to the field of fine chemical engineering. The emulsifier is prepared from octadecylamine, an alcohol solvent, acrylic acid, small-carbon-number tertiary amine, industrial hydrochloric acid, epoxy chloropropane and sodium chloroacetate at the molar ratio of 1 mol:(4.00-9.00) mol: (1.00-1.06) mol: (1.02-1.10) mol: (1.02-1.10) mol: (1.02-1.08) mol: (1.01-1.08) mol. The asphalt emulsifier is prepared from the synthetic raw materials which are easy to obtain and is low in production cost, simple in process, free of high-temperature reactions and capable of emulsifying asphalt of different models; prepared emulsified asphalt is fine, uniform, good in storage stability and suitable for spreading of chip seal coat oil or prime coat oil or tack coat oil of highways; the asphalt emulsifier has the characteristics of a quick-breaking asphalt emulsifier.