A strain-introduced Mach-Zehnder interferometer (MZI) interleaver on lithium niobate (LiNbO₃) is proposed. The structure of the strain-introduced waveguide is designed in detail, and is produced by depositing a SiO₂ film on the annealed proton-exchanged LiNbO₃ waveguide. Considering the sensitivities of the edge strain to the deposition temperature and the thickness of the SiO₂ film, an optimum design of 50 GHz interleaver on this structure is given through analyzing the effective index changes for ^Ex _pq mode by finite difference method (FDM). The length of the bending waveguide in this interleaver is just two thirds of that in the conventional interleaver due to the high refractive index difference.