Influences of different concentration of Al3+ on the roots of pea(Pisum sativum) were studied by determining root elongnation,callose production,activity of peroxide(POD) and hematoxylin stain of root apices after treated by Al3+for 24 h.The results showed that root elongation was obviously inhibited and activity of POD decreased with the increase of Al3+ concentration.Callose content increased with the increase of Al3+ concentration and significantly increased at Al3+ concentration over 50 μmol/L accompanied with heavy hematoxylin stain.These results indicated that Al3+inhibited root growth and the sensitive concentration of Al3+ to root tip of pea is 50 μmol/L.