Cationic emulsifiers are a class of emulsifying agents whose hydrophilic groups acquire a positive charge upon dissociation in aqueous solution. Their molecular structure typically comprises hydrophobic long chains combined with positively charged nitrogen atoms in the hydrophilic group, with quaternary ammonium compounds being the most representative type. These emulsifiers function through strong electrostatic adsorption with negatively charged surfaces, forming robust molecular films at oil-water interfaces while generating electrostatic repulsion to prevent droplet coalescence. Beyond their emulsifying capacity, they demonstrate unique bactericidal, antistatic, and softening properties. Major varieties include alkyl trimethyl ammonium chloride and distearyl dimethyl ammonium chloride, widely employed in hair conditioners, fabric softeners, disinfectant emulsions, and asphalt emulsification. Important considerations include their susceptibility to degradation in alkaline environments and incompatibility with anionic emulsifiers, generally requiring application in acidic to neutral conditions where their distinctive advantages can be fully utilized.