We sampled soil and forage samples from the Hudong area of the Qinghai Lake watershed, China and determined the mineral element contents in the samples. We found that concentrations of selenium in soil and forage samples were significantly lower than normal levels. Thus, there is a plausible severe selenium deficiency in the life forms in the Hudong area of the Qinghai Lake watershed, China. However, we did not discover any clinical sign of selenium deficiency in the critically endangered Przewalski′s gazelle which is living in the area. Presumably, the gazelles have adapted to circumstances of the selenium deficiency. How do the gazelles cope with selenium deficiency? We hypothesized that the selenium content of the forage may differ among forage plant species, which is a major factor affecting the foraging strategy of the Przewalski′s gazelle in the Hudong area of the Qinghai Lake watershed; the Przewalski′s gazelle selects forage with rich selenium as food to cope with the selenium stress. We further sampled and analyzed contents of minerals in soils and forage species from the Hudong area of the Qinghai Lake watershed during the summer grazing seasons of 2006 and 2007. We also reanalyzed the previous results about diet study of Przewalski′s gazelle. We reached following conclusions: shining speargrass (Splendid achnatherum) is a plant with rich selenium and major forage of the Przewalski′s gazelle in the Hudong area of the Qinghai Lake watershed, China. To balance the selenium content in diet, the Przewalski′s gazelle selects grazed on shining speargrass steppe. But, shining speargrass is not a preferred and favored plant for Przewalski′s gazelle.