The invention relates to a quaternized modified amino silicone oil softener and preparation and application thereof. The softener comprises the following general formula in the specification. The preparation comprises the following steps of: (1) adding octamethylcy-clotetrasiloxane into a container, adding a coupling agent N-beta-(aminoethyl)-gamma-aminopropyl methyl dimethoxysilane into the container dropwise, adding a tetramethyl ammonium hydroxide catalyst and subsequently a capping agent hexamethyl disiloxane into the container, and then performing reduced pressure distillation to obtain amino silicon oil; (2) dissolving the amino silicon oil into a solvent, adding the mixture into epichlorohydrin, stirring and heating to react under the protection of nitrogen, and removing the solvent by steaming to obtain an intermediate product; and (3) uniformly mixing N,N-dimethyl-decanamide and the solvent to obtain a mixture, stirring with heating, adding the intermediate product dropwise into the mixture under the protection of nitrogen, performing a thermostatic reaction, and removing the solvent by steaming to obtain the product. The softener of the invention has high hydrophilicity and high stability; fabric processed by the softener has excellent soft handfeel, high hydrophilicity, low yellowing, antibacterial property and the like; and the softener is simple to prepare and is suitable for industrial production.