In this paper, an inviscid, barotropic, nondivergent potential vorticity equation with topography in a β-plane channel is used to investigate nonlinear interaction between a travelling Rossby wave in a uniform basic flow and a single-wave topography with the same zonal wavenumber. It is found that for the CDV-type monopole near resonance, when the uniform zonal basic westerly wind is near the resonant basic westerly wind, 30-60 day low-frequency oscillations (LFO) can arise from the wave-topography interaction. It has both travelling and standing components. In mid-latitudes (30°-45°N), westward-travelling 30-60 day LFO are dominated by Zonal Wavenumbers 1-3, while eastward-travelling 30-60 day LFO are dominated by Zonal Wavenumbers 1 and 3. In high latitudes (near 60°N), 30-60 day LFO are observed to travel westward, and are dominated by Zonal Wavenumber 1. However, for the LG-type (Legras and Ghil, 1985) dipole near resonance it requires a weaker, more realistic basic flow. When the uniform zonal basic westerly wind is near the resonant basic westerly wind, 30-60 day LFO can be excited by the wave-topography interaction. In the mid-high latitudes(30°-60°N), 30-60 day LFO are observed to slowly travel either eastward or westward, depending on the intensity of the near resonant westerly wind, and are dominated by Zonal Wavenumbers 1-3. This demonstrates that nonlinear wave-topography interaction appears to be able to induce low-frequency finite-amplitude oscillations with periods of 30-60 days in the Northern Hemisphere (NH) extratropics.