With the development of spatial data acquisition technology, the surveying departments have acquired mass DEM Data at terabyte-scale. The current GIS software and computing methods can not meet the demand of analyzing and mining these mass data. A new kind of computing infrastructure is expected to support distributed access to and analysis of these datasets by potentially thousands of users. Grid computing has emerged as an important new field, distinguished from conventional distributed computing by its focus on large-scale resource sharing, innovative applications, and , in some cases, high-performance orientation. This paper focuses on the key problems of terrain analysis of mass DEM data based on grid computing and makes the following contributions. First, we review the current terrain analysis algorithms based on DEM data and analysis the parallel algorithms. Next, we proposed a DTA (Digital Terrain Analysis) grid and analyze the architecture and key problems of the DTA grid. Finally, the experiment system developed based on grid middleware is introduced.