A new kind of flexure hinge, which was used on LEMs, named Triple—LET was proposed via connecting three outside LET flexure hinges, and its 3D structure was designed and analyzed. The equivalent bending stiffness of the Triple—LET flexure hinge was deduced and a modified coefficient was presented to optimize the results. Based on the modified formula of equivalent bending stiffness, the theoretical calculation of the design example was deduced，and the finite element simulation model of the design example was established and analyzed. Through comparing theoretical calculation results with finite element simulation results of the design example, the feasibility of the Triple—LET flexure hinge was verified. In order to verify the availability of the new flexure hinge in practical application, the Triple—LET flexure hinge was applied to a lamina emergent slider mechanism. The pseudo-rigid-body model of the lamina emergent slider mechanism was established based on the modified equivalent bending stiffness, and the physical model of the lamina emergent slider mechanism was made of beryllium bronze material based on the series Triple—LET flexure hinge. The theoretical calculation results and experimental results were basically consistent, therefore, the correctness of the theoretical model and the feasibility of the design example were verified, and it also indicated that the lamina emergent slider mechanism can implement large deformation and maintain a good stability in working status.