The invention discloses low-viscosity skin-care emulsion and a preparation method thereof. The preparation method comprises the following steps: firstly, weighing the following components by weight percentage according to a formulation: 1.0 to 3.0 percent of main emulsifying agent, 1.0 to 3.0 percent of auxiliary emulsifying agent, 0.4 to 0.8 percent of stabilizing agent, 17.0 to 27.0 percent of emollient, 0.6 to 1.6 percent of preservative, and the balance being additive and deionized water; and then adding an oil-soluble component into an oil-phase pot, adding a water-soluble component into a water-phase pot, heating the pots respectively, extracting raw materials in the oil-phase pot and the water-phase pot into an emulsifying pot to homogenate the mixture, later cooling the mixture, adding residual components into the mixture, and discharging the skin-care emulsion. The viscosity of the low-viscosity skin-care emulsion prepared by the method is between 1,500 mpa.s and 3,000 mpa.s, emulsion centrifugation does not cause oil-water separation phenomenon, the viscosity of the emulsion is affected by temperature little, and at the same time, the production method for the emulsion has the advantage of simple process and can produce the emulsion by using the prior producing technique and equipment.