Abstract: An elliptical surface plasmonic waveguide with a high refractive index substrate is designed. Dependences of energy flux density distribution, effective refractive index, propagation length, effective area of the fundamental mode supported by the waveguide on the geometrical parameters and structure are analyzed based on the finite element method. The energy density distribution show that the energy is mainly distributed in the central region between two metallic elliptical cylinders, and there is also energy between the metal and germanium substrate，the substrate and substrate. Propagation characteristics of the waveguide mode can be analyzed by adjusting the centric distance of two ellipses and size of two semiaxis. With constant working wavelength, the effective refractive index decreases with increasing of center distance, while the propagation length increases.

Key words: fiber and waveguide optics; metalic elliptical; surface plasmonic waveguides; effective refractive index; propagation length