To study the characteristics of heavy metal absorption and accumulation of Pennisetum giganteum and the repairing effects on the contaminated soil by heavy metal, the phytoremediation test of Pennisetum giganteum was carried out in the Cd and Hg contaminated acid soil and 2 treatments of Pennisetum giganteum and nano-heavy metal enrichment agent were also set up. The results showed that the contents of Cd in the roots, stems and leaves of Pennisetum giganteum decreased, the contents of Pb, Cr and Hg were the highest in the roots, the lowest in the stems, and the contents of As in the leaves, roots and stems decreased. The accumulation of Cd in the stems was greater than that of leaves. The accumulation of Cr in leaves was greater than that of stems. Pb, As and Hg were leaf accumulation types with more than 80% of the whole in leaves. The primary transport indexes of Cd were 4.2, 7.2 and 2.4 times of Pb, Cr, As, respectively, which indicated the migration ability of Cd from root to stem was strong. The secondary transport indexes of Pb, As and Hg were 8.4, 8.8 and 12.7 times of Cd, respectively, which indicated the migration ability of Pb, As and Hg from stem to leaf were greater than that of Cd. The Cr had poor mobility in Pennisetum giganteum. The Cd enrichment of the upper part of Pennisetum giganteum was 82.96 g/hm2. The bio-enrichment factor of Cd was 38 231 kg/hm2, and the soil Cd extraction efficiency was 1.699%. The Cd content in the soil was reduced by 2.90% compared with the background value. The translocation factors of Cd, Pb, Cr and As with addition of nano-heavy metal enrichment agent were increased by 5.09%, 30.88%, 4.48% and 49.72%, respectively, and their secondary transport indexes were increased by 11.39%, 45.25%, 59.52% and 53.58%, respectively, which indicated nano-heavy metal enrichment agent promoted the migration of heavy metal elements in plants. The phytoremediation test of Pennisetum giganteum was also carried out in Cd contaminated acidic soil with 2 treatments of Pennisetum giganteum and blank control. The results showed that compared with the blank control, the contents of As, Hg, Cd, Pb and Cr in the soil with Pennisetum giganteum were decreased by 6.16%, 4.75%, 4.91%, 2.77% and 2.42%, respectively, and except for Cd their difference reaching a very significant level(P<1%). Compared with the background value, the contents of Cd, Pb, Cr, As and Hg in the blank control soil were increased by 3.89%, 1.98%, 8.10%, 0.74% and 20.36%, respectively, indicating that environmental factors such as atmospheric deposition had an important influence on the accumulation of heavy metals in farmland soil.