Effect of nitrogen of different forms on Sorghum sudanense root morphology and lead(Pb) absorption and accumulation under Pb stress were studied using hydroponics experiment，addressing the interaction between the plant and different nitrogen forms and heavy metals for phytoremediation application． The results indicate that the different N forms had some insignificant effects on the root morphology of S． sudanense with Pb pollution level of 0． 5 mmol/L． However，the MDA(Malon dialde hyde)contents of the roots and the biomass of each organ of S． sudanense were significantly(p ＜0． 05) influenced: the MDA content of S． sudanense root in the NH4-N culture solution was 4． 6 and 1． 6 times higher than those in NO3-N and NO2-N culture solutions，and the root，stem and leave biomasses in the NO3-N culture solution were higher than those in NH4-N culture solution by 28． 7%，19． 6% and 23． 9%，and higher than those in NO2-N culture solution by 37． 6%，30． 9% and 36． 7%，respectively． With Pb pollution level of 0． 5 mmol/L，the root in NO3-N treatment had the largest enrichment coefficients and Pb concentration that was over 2 times higher than that in NH4-N culture solution，and Pb concentration of the stem in the NO2-N treatment was over 8 times higher than that of NH4-N treatment，indicating a high transport capability of Pb． This suggests that if the existence of different forms of nitrogen in the eutrophication water with heavy metal pollution may to some extent weaken the toxic effect of the heavy metal on the remediating plant，and increase the environment capacity of the water．