The invention discloses an interpolation method for a DEM (Digital Elevation Model) generated by contour lines. The interpolation method comprises the following steps: 1, acquiring and loading vector contour line data meeting specific conditions, wherein the specific conditions are: each contour line is spatially and continuously distributed and cannot be interrupted, and odd contour lines and even contour lines exist at intervals; 2, performing morphological corrosion reconstruction and morphological expansion reconstruction to generate a lower plateau image and an upper plateau image respectively; 3, performing obstacle Euclidean distance conversion to acquire a geodesic path and a geodesic distance, and performing pipelined linear interpolation to generate the DEM. The generated DEM has the characteristics of high accuracy and high fidelity and is generated by using the linear interpolation method, the DEM accuracy obtained under the condition that only contour line data are used is equal to or higher than the DEM accuracy obtained by using a map algebra method, manual intervention is not needed, the DEM is not limited by iterations, an adaptive algorithm is truly achieved, and the interpolation method can be applied to various industries.