To effectively detect the bend-type structure, the finite element method (FEM) and experimental modal analysis (EMA) are employed to generate the modal flexibility of the bend-type structure. Then the modal flexibility is used to compute modal flexibility curvature and difference by using the central difference method. Different severities, locations and the number of damage are simulated by additional quality in the intact bend type to verify the modal flexibility curvature and difference generated by both FEM and EMA. The results show that the modal flexibility of bend-type should have the direction. In addition, it can be obtained that using the plane x, y direction to solve the modal flexibility curvature difference cannot bend damage identification methods for damage identification. However, using the vertical pipe where the plane z direction of the bending flexibility, the multiple damage location, and quantitative analysis for the extent of injury to the same location can be carried out.