—Proteins are the main players in the game of life. Good understanding of their structures, functions, and behaviors leads to good understanding of drugs, diseases, and thus our health. So, much effort has been done to study and categorize proteins. Nowadays, tens of thousands of proteins have been found. Moreover, the problem of comparing the proteins is hard. Therefore efficient methods are needed to deal with this problem. In this paper, we used one important computational geometric method and one graph matching method: ”Delaunay Tetrahedralization” and ”Similarity Flooding” to propose a new idea to extract similar parts of proteins by combining both of these methods.