The present invention relates to a cosmetic composition comprising slime of snails fed with berry fruits and a preparation method thereof. In particular, the present invention relates to a composition comprising slime of snails fed with berry fruits and a preparation method thereof, wherein snail slime obtained from snails fed with berry fruits enhances skin regeneration, skin elasticity, and moisture by means of mucin, collagen, and elastin contained in the snail slime such that an active oxygen in skin can be decreased and skin aging can be prevented by polyphenol contained in the berry fruits, and the slime of snails fed with berry fruits in the cosmetic composition of the present invention is harmless to a human body as a natural raw material and prevents skin problems by reducing skin stress caused by external environments.