Tandem repeat structures are widely distributed among all classes of proteins. Various basic structural units of repetitive nature possess functional diversity and reflect important influences on biological responses for different organisms. One of the most common types of protein repeat structure is the α-solenoid tandem repeat class which possesses low sequence similarity between any two repeat units within a structure. Therefore, a successful segmentation system for identifying each repeat unit cannot be achieved mainly based on sequence comparison approaches. For a comprehensive analysis on fundamental repeat unit segmentation, subclass identification, and functional annotation on such repeat structures, we have developed an automatic segmentation system according to geometrical coordinates and physical characteristics. Dihedral angles of Psi and Alpha were applied to define the range of candidate α helix elements, and the included angle between the vectors formulated by previously defined neighboring α helix elements was analyzed for constructing a fundamental repeat unit. To evaluate the performance of our developed prediction system, we employed 923 protein structures collected in the RepeatsDB database and clustered as α-solenoid repeat class. The testing result has shown that our proposed system could achieve a recall rate of 92.39% and a precision rate of 93.52%, respectively.