The effects of light propagation direction on the stress induced polarization dependence of silicon-based waveguide were studied. As silicon is an anisotropic material, the change of polarization dependence induced by the photoelastic effect depends on the light propagation directions. It is found that when the light propagates in <100> directions on {100} silicon, the changes of refractive index and polarization shift are about 20% more sensitive to the stress than those when the light propagates in <110> directions. (IEEE Photonic Technology Letters, vol. 18, No. 12, June 2006)