Abstract: Mapamyum Co and the south slope of pengzhe feng of gengdise shan are situated about 4505 to 6124 meters in altitude. Their ecological conditions are unfavourable and climate is severe. There are thin air, stroung constant wind, low rainfall, excessive evaporation and low temperature, although the diurnal range of temperature is great. In addition, the sunshine is abundant and the solar radiation is intensive. The growth period of plants is very short. The seed plants colleted from the districts comprise 111 species belonging to 76 genera of 27 families. Among them, two species are new to science. The flora of the districts belongs to Chinese Himalayan floristie subregion. Adapting to the unfavourable habitat, a great mant alpine plants are pulvinate, resular, repent, or densely clothed with matted wool. The vegetative reproduction exceeds the sexual reproduction. The essential plant communities of the districts are as follows: 1. Deciduous undershrub of Caragana versicolor Benth. and Artemisia mattfeldii Pamp. var. etomentosa Hand.-Mazz. distributes on the slope between 4700 and 4880 m above sea leval. 2. Cushion vegetation of Caragana versicolor Benth., Potentilla arbuscula D. Don var. pumila (Hk. f.) Hand.-Mazz. and Thylacospermum caespitosum (Camb.) Schi- sch. distributes on the slope between 4880 and 5110 m. 3. Cushion vegetation of Thylacospermum caespitosum (Camb.) Schisch and Arenaria musciformis Wall. distributes on the slope between 5110 and 5450 m. 4. True steppe of Stipa gloreosa P. Smirn. and S. purpurea Griseb. distributes on the well drained plain between 4530 and 4600 m. 5. Undershrub steppe of Stipa gloreosa P. Smirn. S. purpurea Griseb. and Caragama versicolor Benth. distributes on the foothill between 4600 and 4700 m. 6. Swam meadow of Blysmus compressus (L.) Panz. and Potentilla anserina L. distributes in the lake district between 4505 and 4530 m. In the districts, many superior herbage may be encountreed, as Polygonum viviparum L., Orinus thoroldii (Stapf) Bor, Stipa gloreosa P. Smirn., S. purpurea Griseb., Blysmus compressus (L.) Panz. and Kobresia stenocarpa (Karet et Kir.) Steud and so forth, otherwise, there are many valuable medical plants, as Arenaria musci- formis Wall., Hypecoum leptocarpum Hk. f. et Thoms., Rhodiola himalensis (D. Don) Fu. Oxytropis microphylla DC., Saussurea tridactyla Sch.-Bip. and others.