The invention provides a softening agent containing hydroxyl silicone oil and a preparation method thereof. In parts by weight, the softening agent comprises components: 30 to 80 parts of hydroxyl silicone oil with a viscosity of smaller than 20cs, 10 to 30 parts of sodium stearate, 30 to 80 parts of trimethylamine, 10 to 30 parts of dihexadecyl dimethylamine methylsulfate, 20 to 60 parts of sodium silicate, 5 to 20 parts of PEG-120 distearate and 300 to 500 parts of water. The water is heated to 40 to 60 DEG C and then is added into the rest of components to stir and uniformly mix, and the mixture is cooled to the room temperature so as to obtain the softening agent. According to the softening agent and the preparation method thereof, which are provided by the invention, various components, such as the hydroxyl silicone oil and the like, are combined with stearic acid together, the components do not need to be heated to a temperature of over 70 DEG C to dissolve the stearic acid in the preparing process, and the softening agent is easier to prepare. Moreover, the softening agent provided by the invention has an excellent use effect and does not damage surfaces of fabrics.