We propose a lightweight method for constructing a global digital elevation and terrain database in consideration of the satellite flight path. First, a global maximum/minimum elevation database with a grid size of 0.05° × 0.05° was generated using Shuttle Radar Topography Mission data and the Global Multi-resolution Terrain Elevation Data along with other multi-source digital elevation model (DEM) data. A global database of maximum terrain fluctuation with a grid size of 0.05°× 0.05° and distances of 140 and 700 m was then constructed on the basis of the ICESat-2 satellite flight path and the main frame/super frame distance criterion. The databases, which achieve global coverage while occupying a small storage space, can be used to assist in the in-orbit preprocessing of onboard data. The database accuracy was evaluated using ICESat-2 data. In the 10 validation areas, the global DEM database had an error of only 3 m in two validation areas, and the error was less than the accuracy range of each DEM data source. The global terrain database can characterize the degree of surface relief in each verification area, confirming the effectiveness of the method used in this study.