A protein molecule is made of a long chain of amino acid sequences that fold into a complex three-dimensional structure. It is often the geometrical shapes that determine the protein functions. In molecular biology, researchers use sequence alignment and structure matching to compare the similarity among proteins. Considering proteins as 3D structures, we propose a novel algorithm to identify geometry-based features to retrieve similar proteins without having to deal with complex chemical characteristics and biological properties. A web-based Dali server, which performs well in three-dimensional structure matching, is used as the ground truth to evaluate our algorithm. Our system performs close to the ground truth with much simplicity and efficiency.