The invention discloses a
quaternary ammonium salt cationic surfactant and a preparation method thereof. The preparation method comprises the following steps: adding a
dimethylamine aqueous solution and linear chain dimethyl
alkyl tertiary amine selected from 10 to 18 carbon atoms into 1-
chlorine-2,3-epoxypropane, wherein the
molar ratio of the linear chain dimethyl
alkyl tertiary amine to the 1-
chlorine-2,3-epoxypropane to the
dimethylamine is 1.0:(4.0 to 20.0):(3.01 to 20.01); heating to 70 to 90 DEG C and reacting; and finally removing non-reacted materials to obtain the surfactant. The method does not need
high pressure and high temperature and avoids three wastes, so the method has the characteristics of environmental friendliness, and safe and simple process. The cationic surfactant obtained by the method has low
ecotoxicity, no
irritation to a
human body and good water
solubility, has high
charge density, has cleaning, foaming, sterilizing,
algae-control, anti-static and anti-
fog functions, particularly embodies good
cost performance on space disinfection and water sterilization, and has the characteristics that the surfactant is non-toxic and harmless to a
human body, is easy to decompose and has good anti-
fog and anti-static effects.