Abstract: By measuring productivity with quadrat sampling method on the circles and inside , outside the circles of Agaricus arvensis fair ring, the differences of the community among them were analysed. The results showed: A. arvensis circles could promote the above ground biomass of the community obviously. Especially, the effects of A. arvensis circles on Leymus chinensis were greater. Th e above ground biomass and density on the circles were higher than those of inside, outside the circles; the height and weight of individual plant on the circles were similar to those of inside, outside the circles; the effects on other plants were not obvious. A. arvensis circles can promote plant’s ability to absorb water.