The invention discloses a moisturizing cosmetic and a preparation method thereof. The moisturizing cosmetic is prepared from the components of rosa damascena extract, rosa canina fruit oil, undaria pinnatifida extract and the like. By adopting the unique prescription, the cosmetic can form a protective barrier on the surface layer of the skin of a user, ensures high skin absorption rate and good moisturizing effect, can effectively prevent the skin from being dry, and has the advantages of no skin stimulus or allergy to the skin, security and effectiveness.