After the evolution of hundreds of millions of years, most turtles have developed excellent shells with high specific stiffness and toughness. Obviously, the multi-scale structural characteristics and the biological material mechanical behavior of these turtle shells can be used for promoting the bio-inspired design of safety protection structures. This paper reviews the research progress of the turtle shell relevant to its protective functions, including the macro and micro features of the carapace and the corresponding mechanical properties. In addition, some carapace-inspired designs that could be adopted in protection structures are summarized. Finally, the existing problems and the focus of the future research are discussed, to provide some food for thought in the bio-inspired design of safety protection systems in future.