Abstract: The smart structures and special functions of natural biomaterials provide some biomimetic clues for solving many technical problems in engineering. Ones have been finding the imitative or biomimetic objects and paying an attention to how to transfer a biological system into an engineering system.Keratin materials is a naturally biological composite material which possesses different structure and property from other biomaterials. The structure and ultrastructure of the keratin materials have considerable effects on their mechanical behavior. The understanding of the structure as well as ultrastructure of the keratin materials should be very useful to design biomimetic materials and biomi metic systems in engineering including agricultural engineering. The structures and their effects on mechanical properties of such keratin materials as hoof wall, feather, hair and claw were reviewed. The analytic methods of beratin materials were summarised as well.