The invention discloses yeast water and a preparation method as well as application thereof to cosmetics. The preparation method comprises the following steps: fermenting yeast, performing solid-liquid separation so as to obtain supernate, mixing the supernate with adsorbent, heating to react, and filtering so as to obtain yeast water A; washing the obtained bacterium with water, drying, crushing, further adjusting the temperature to minus 25 DEG C to minus 20 DEG C, after refrigeration ice crystallization of yeast cells, and crushing for at least minus 25 DEG C to minus 5 DEG C so as to obtain yeast cell micro powder; mixing the yeast cell micro powder with purified water, performing ultrasonic extraction, and filtering so as to obtain yeast water B; combining the yeast water A with the yeast water B, adding purified water to adjust till the content greater than effective concentration, adding an antioxidant and a preservative, thereby obtaining yeast water. The yeast water can remarkably reduce the smell of distillers' grain or adverse special fermentation smell, has outstanding beautifying effects and is applicable to preparation of cosmetics with effects of aging resistance, wrinkle resistance, beautifying, whitening and speckle paling.