Abstract: With the organic polymer ridge waveguide as the research object, the polarization characteristic of symmetric ridge waveguides with different ridge heights, ridge widths and core thicknesses were systematically analyzed by a semi-vector finite-difference beam propagation method(FD-BPM). Furthermore, the polarization characteristics of asymmetric ridge waveguides were analyzed, and the influence of the shorter side width of the core to the polarization characteristic is studied. The result shows that the introduction of asymmetric ridge structure has a minor effect to the polarization characteristic, and the birefringence decreases along with the reduction of the shorter side width of the core. The birefringence of the asymmetric ridge waveguide can be controlled in an acceptable range when the ridge height is 1.3 m and the shorter side width of the core is 2.0 m.