A way to interpreting patent claims is two: one is the central definition and the other is the peripheral definition. The central definition is originated from the very beginning of the era of establishing patent acts when the claiming method was not established yet. When claiming invention, the inventor only describes the general inventive idea. During patent infringement litigation, the court extends the general inventive step to the equivalent variations of the invention. It is evitable that the gap exists between the claimed inventions and the extent of protection. On the contrary, according to the peripheral definition, the claims posts the fence of the outer boundary of a property rights. Then the boundary of the claims of invention accords with the boundary of patent protection. These principles are connected with theories of the relationship between interpretation of patent claims and the fixation of patent protections: one theory is that both are different; the other is that both is the same. The central definition doctrine originates from the U.S. Patent Act and patent practice but Germany develops after Germany enacted the 1877 patent act. In Korea, the Korean patent law has been practiced with the peripheral definition doctrine. Nevertheless, there are two theories in Korea. In this study, from the central definition doctrine developed by Germany, I try to provide a propose of interpretation of patent claims.