Based on the meteorological data and the grass, data from 1987 to 1996 in Tiebujia, Qinghai Province, the influence of the rainfall, soil humidity,evaporation capacity on the height and yield of five dominant species of natural grass is investigated in the Tiebujia grassland, near the Qinghai Lake. The result shows that the yield ratio of Stipa purpurea,Poa crymophila, Carex aridula, Artemisia scoparia, Leymus tianschanicum and miscellaneous is 8∶15∶15∶16∶18∶28.The drought-resistance from high to low of 5 species of natural grass is Leymus tianschanicum,Carex aridula,Artemisia scoparia,Stipa purpurea , Poa crymophila. The most of grass′s critical period of water requirement is in June. It is important for the drought-resistance.