In order to study the root, leaf, stem and seed of barnyard grass absorbing fluoride from soil, a cultivated experiment of barnyard grass was carried on in a net room using 11 natural soils. After determining the fluoride content in the root, leaf, stem, seed of barnyard grass, the order of fluride content in them from high to low is root>leaf > stem>seed. The result of statistics indicated that there is a positive correlation betweenfluoride content in root of branyard grass and with that in soil, but there is no correlation of fluoride content in leaf, stem, seed with that in soil. This indicates that the fluoride content in soil has no obvious affect on them. The biological absorption coefficients of fluoride by these four parts of barnyard grass is blong to O.n grade, and fluoride is a middle-absorbing element by barnyard grass. It also shows that fluoride can not be accumulated in the barnvard grass. and still more can not be accumulated in its seed.