Bed topography in river bends is highly non-uniform as a result of the spiral motion of fluid and sediment transports related to channel curvature. To grasp a full understanding of geomorphology and hydrology in natural river bends, detailed bed topography data are necessary, but are usually not of high enough quality and so require further interpolation for sophisticated studies. In this paper, an algorithm is proposed that is particularly suited to bathymetry interpolation in rivers with apparent bends. The thalweg and the two banks are used as geographical features to ensure that a concave cross-sectional bed-form can be found in bend geometry, while linear interpolations are conducted in the in accordance with secondary and main stream currents, respectively. In comparison with conventional spatial interpolation methods, the proposed algorithm is validated to ensure better performance in generating smooth and accurate bed topography in channel bends, which results in better predictions of river stage by 2D hydrodynamic simulation in practical field tests.