Aiming at the low efficiency of A ^* algorithm in Digital Elevation Model (DEM) path planning, an improved A ^* algorithm based on distance and slope was proposed. A new evaluation function were designed by using distance and slope regarded as evaluation indexes in regular grid digital elevation model, and the pathability of surface barrier was judged. And in order to ensure that the improved algorithm was adaptive to the changing of the resolution ratio for DEM data, the parameters of the evaluation function were calculated according to the DEM data of the actual scene in the path searching process. Finally, a dynamic weight was changed with the changing of path searching, which could optimize path selection by adjusting the influence of completeness function and heuristic function on evaluation result. The simulation results show that the improved algorithm can adapt to the changing of DEM resolution by parameter adjustment, search the optimized path, reduce the search time and improve the search efficiency.