Abstract: Aiming at the characteristic of multi-data and evident anisotropy of DEM Construction in intertidal zones (IZDEM), a new method based on combining optimal trend surface and Kriging interpolation is proposed. First, an optimal trend surface is obtained using an optimal equivalent weight to control the influence of precision difference between different source data to the quality of IZDEM. Then, corresponding residuals surface is constructed by kriging interpolation to recapture finer details lost from smoothing. IZDEM is constructed by combining optimal trend surface and residuals surface. Experimental results demonstrate that the proposed method has improved the quality of IZDEM.