In this paper, the distribution and movement of lead in the air soil wheat ecosystem around the 107 # state road were studied. The lead density (LD) in the air varied with a positive propotion to traffic volume, but there was no obvious correlation with wind speed and air temperature. The LD in soil or wheat organs, which showed a negative propotion to the distance from the state road, had two suddenly dropping points at 5m and 60m, but only a very little movement in soil from upper to lower layer, o...