Abstract: 68 quadrats were divided into eight types of communities by TWINSPAN, which can be treated as one-dimension resource states. The niche breadths and overlaps of main dominant species were measured using a series of indices proposed by Levins, Shannon-wiener and Petraitis. Among general communities, Carex lanceolata and Poa pratensis niche breadths value being biggest prove that adaptive capacity to community’s environment are the strongest, the ability to use resources is the strongest too. In different communities (community Ⅰ to community Ⅷ), niche breadths are great difference to the same specie-pairs, Poa pratensis niche breadths in community Ⅱ, B1 is 2.753, B2 is 15.561; in community Ⅷ, B1 is 0, B2 is 1; In the general community, the niche breadths of specie-pairs are obviously greater than in other community. The larger the niche overlap of two species is, the more similarly resource space they occupy. the niche overlap of Leontopodium leontopodioides and Polygonum viviparum amounts to 0.892 (in the community Ⅰ). This proves that they are very similar in utilizing the resources. In the general community, the niche overlaps among species are very low.

Key words: the Midst of Taihang Mountain, niche breadth, niche overlap