Abstract: Fluorides pollution in the region around the Aluminium-smeltery in Lanzhou has been studied and described. The results showed that fluorides pollution in the air had caused contamination of soil and plants. Air, soil and plants were polluted within a radius of 4000 to 7500 meters from the emission source, visible symptoms were produced in the plants. The normal growth of various plants was inhibited. In the sensitive species, for example apricot (Prunus persica) and peach (P. armeniaca) the fruits dropped early and had poor quality, and the yield was decreased. Wheat grew and developed poorly. Scallion and garlic bulbs had lost much of their food value.The results of fluorides content showed that the fluorides concentrations were different in various parts of plants. The fluorides concentrations in leaves were the highest. Fluorides concentrations in plants, soil and airborne particles decreased with increase of distance from the emission source. Damages to plants were intensified with the increase of fluorides contents. For this reason, the fluorides contents and damages of plants are concrete indications of the degrees or ranges of pollution (as indicators of air pollution). Thus the region around the Aluminium-smeltery may be divided into four areas according to pollution: clean area, lightly polluted area, polluted area and heavily polluted area.These conclusions are based on the determinations of 235 samples of air, 127 samples of soil and 362 samples of plants collected at 18 measurement points established around the alminium smeltery in its north, northeast, southeast and south within a radius of 2–4km with the radius in the leeward direction increased to 7.5km,