Didecyl dimethyl ammonium bromide is a quaternary ammonium salt cationic surfactant, which is a light yellow transparent liquid with poor water solubility. It has the function of sterilization and disinfection, and its activity is reduced in the presence of non-ionic detergent. It can be used as disinfectant, antiseptic and mildew inhibitor. It can also be used as an asymmetric phase transfer catalyst, especially suitable for the oxidation reaction catalyzed by ruthenium trichloride.