格尔木地区地处内陆极干旱区，水资源分布不均衡。区内生态系统与地下水水位密切相关。随着地下水开采的加剧，区域地下水位下降，绿洲带泄出量减少，将可能造成绿洲带植被退化。文章通过综合分析格尔木河冲洪积扇水文地质条件，应用Visual Modflow软件，建立了水文地质条件概念模型及数学模型，分别预测了地下水现状开采和扩大开采10年后，丰、平、枯水期地下水水位的升、降情况及其对下游绿洲带的影响。结果表明：扩大开采量开采10年后，在丰水期，不会影响绿洲带的物种,土壤含盐量适宜时苔草分布范围可能会扩大；在平水期，绿洲带的分布和物种基本上维持现状；在枯水期，对苔草的生长有负面影响，其生长范围和覆盖度都会变小。

The water source of Geermu which was in inland arid region was imbalance. With the gradual enlargement of the scale of Geermu water source mining, regional underground water level was decreased, and the overflow downstream was reduce, leading to vegetation degradation of oasis. Geermu River’s alluvial and flood fan hydrogeologic conditions were analyzed in this article. Visual Modflow was used to build a model on groundwater, aiming at impact prediction on oasis band downstream with decreasing of regional underground water level after the expansion of the gradual enlargement of the scale of Qingxia water source upstream in decades. The results showed that the oasis species were not affected by expanding mining, and the distribution of sedge would extend while soil salt content was suitable in wet season. The above results were standstill in normal water period and contrary in dry season.