目前三角网是进行精细地形表达最好和最常用的方法，因此本文讨论利用三角网法来建立露天矿的精细DEM模型。由于露天矿复杂特殊的地形特征，在建模过程中应充分考虑相应的约束条件，否则会出现台阶被削平等现象。构建不规则三角网的方法可分为分而治之算法、逐点插入算法和三角网生长算法。各种算法各具优缺点，结合矿区的实际情况，本文采用一次性约束三角网生成算法，经过空间数据提取、拓扑关系建立以及空间索引建立，最终建立起边界约束线以内的约束不规则三角网。-At present, triangulated irregular net is the best method of fine landform expression, so the paper discusses applying triangulated irregular net to establish fine DEM of open-pit. Because of complicated landform characteristic, corresponding constraint condition should be considered in building model process, otherwise it will appear phenomenon that flight of steps is cut. The method of triangulated irregular net establishment is detachable for divide and conquer algorithm, piecemeal intervene in algorithm and triangle net growth algorithm. The various algorithm has excellence and shortcoming respectively, combined with the mining area actual situation, this paper adopt the constrained triangulated irregular net once generation algorithm, through spatial data extraction, topological relations generation and spatial indexing generation, constrained triangulated irregular net is generated within boundary line at last.