【Objective】 A pot experiment had been carried out to investigate effects of soil amendments (pig manure compost, humic acid, EDTA) and a switched polarity DC electrical field on phytoremediation of Cd contaminated soil with hyperaccumulator Sedum alfredii. 【Method】 In this experiment, plants of Sedum alfredii, a species of hyperaccumulator, were planted into pots containing loamy soil pretreated with 15 g kg^-1 of pig manure compost, 10 g kg^-1 of humic acid, or 5 mmol kg^-1 of EDTA, separately, as treatments and with nothing as control. In addition, the pots were subjected to another treatment: no-voltage (without electrical field) or direct current (DC) electrical field (1 V cm^-1 with switching polarity every day). At the end of the experiment, dry weights of shoots and roots of the plants, cadmium (Cd) concentration in the plants and soil available Cd (diethylene triamine pentaacetic acid (DTPA) extractable) were determined. 【Result】 Available (DTPA extracted) Cd in the soil increased significantly in the treatments subjected to DC electrical field and amended with pig manure compost, humic acid, or EDTA. The former increased DTPA-extractable Cd by 6.06%~15.64%, while the latter did by 5.74%~7.16%, 8.80%~10.32% and 4.77%~5.91%, respectively, with DC field on and by 2.84%~3.32%, 7.70%~9.47% and 7.10%~7.75%, respectively, with DC field off. Cd concentration in the plant shoots significantly increased in the pots with DC field on, varying in the range of 226.2~313.7 mg kg^-1, and lingered in the range of 178.7~212.6 mg kg^-1with DC field off. Soil amendments (pig manure compost, humic acid, EDTA) also had significant effects on Cd concentration in the plant shoots (p<0.05). In addition, Cd concentration in the plant shoots was increased by 7.33%~37.0%, 19.0%~38.7% and 6.13%~12.0% by the addition of pig manure compost, humic acid and EDTA, respectively. By switching the polarity of the DC electrical field, significant pH variation from anode to cathode can be avoided, and thus no significant impact was observed on shoot biomass of the plants. Soil amendments (pig manure compost, humic acid, EDTA) had significant effects on shoot biomass of the plants (p<0.05). The addition of 15 g kg^-1 pig manure compost and 10 g kg^-1 humic acid increased shoot biomass by 40.3%~43.7% and 16.3%~18.2%, respectively, while the addition of EDTA decreased shoot biomass by 7.3%~7.5%. Cadmium concentration in shoot and plant shoot biomass are the most crucial factors for determining efficiency of the phytoextraction. The findings in this pot experiment demonstrate that DC field increases significantly (p<0.01) Cd accumulation in the plants in all the treatments, as compared with those with DC field off. Cd accumulation in shoots of the plants was in the range of 2 088~4 014 μg pot^-1 with DC field on, and 1 677~2 635 μg pot^-1 with DC field off. In addition, Cd accumulation in shoots of the plants was increased by 54.3%~92.2% and 38.4%~63.9% in the pots pretreated with pig manure compost and humic acid, respectively, because of their simultaneous effects of increasing Cd concentration in shoots and shoot biomass. However, no noticeable effect was observed in the EDTA treatment in comparison with the control, which can be ascribed to the inhibition of plant growth by EDTA. The combined use of pig manure compost-DC field and humic acid-DC field enhanced Cd accumulation in shoots by 134% and 100%, respectively. 【Conclusion】 Based on the findings, the amendment of pig manure compost or humic acid coupled with switched polarity DC electrical field could significantly enhance Cd phytoextraction by hyperaccumulator Sedum alfredii.