Abstract: In order to understand community status of the genus Eriocaulon L. (Eriocaulaceae), the ecological condition of the area for growth of Eriocaulon species was investigated and the speciesdiversity of Eriocaulon were studied. The key to species was constructed based on the morphological characters of Eriocaulon in the Eld’s Deer sanctuary Savannakhet Province. The ecological condition of area included the diversity of plants, canopy cover and pH values and soil contents in P, N, and K. This study collected data in the sampling plots 20×20 m in 4 typical area including Grassland, Dry Dipterocarp Forest, Mixed Deciduous Forest and Savannah, 3 sampling plots per each typical area were established. The diversity of plants in 4 typical area were as follows: the total of the diversity of plant in the study area in 12 sampling plots have been 124 species from 46 families. The canopy cover showed the different percentage of canopy cover in each plot of 4 typical area. Grassland did not have the canopy cover, Dry Dipterocarp Forest presented the canopy cover 21.50-25.75%, Mixed Deciduous Forest presented the canopy cover about 58-64.50%, Savannah presented the canopy cover about 6.25-10.25%. The pH value in Grassland from the lowest to the highest is 4.9-5.9 and content of N, P and K are: N 84-165.2 mg/kg, P 0.88-2.12 mg/kg, K 9.38-27.76 mg/kg. The pH value in Dry Dipterocarp Forest from the lowest to the highest is 4.9-5.9 and content of N, P and K are: N 98-176.4 mg/kg, P 1.78-2.7 mg/kg, K 29.72-92.28 mg/kg. The pH value in Mixed deciduous Forest from the lowest to the highest is 4.8-5.2 and content of N, P and K are: N 103.6-134.4 mg/kg, P 0.58-2.62 mg/kg, K 17.2-44.18 mg/kg. The pH value in Savannah from the lowest to the highest is 4.8-6.2 and content of N, P and K are: N100.8-165.2 mg/kg, P 0.52-2.49 mg/kg, K 21.9-109.48 mg/kg. For the diversity of Eriocaulon in this study recorded the 12 species include Eriocaulon cinereum, E. echinulatum, E.hamiltonianum E. infirmum, E. nephalense var. luzulaefolium, E. phuchongense, E.phuphanoides, E. siamense, E. smittinandii, E. thailandicum, E.truncatum and E. zollingerianum. All species of Eriocaulon are constructed the key to species based on the morphological characters of Eriocaulon in the Eld’s Deer sanctuary Savannakhet Province and descriptions all species of Eriocaulon