In order to verify the effectiveness of long-term application of the technology of inter-cropping remedying heavy metal contaminated soils, a 3-year field experiment was conducted to have three treatments and 5 croppings, Treatment IC (inter-cropping of Sedum alfredii Hance and corn (Zea mays)), Treatment Mono-cropping ( Sedum alfredii Hance ) and Treatment IC + MC (mixture of chelators consisting of citric acid and EDTA). Plant yields and heavy metal contents in plant and in soil were monitored for comparison. Results show that the total Cd and Zn in the soil decreased continuously with the progress of the experiment. After the 5 croppings, the soils in Treatments IC and IC MC were remedied to meet the criteria of the National Standard for Soil Environmental Quality (GB15618 -1995). Soil Cd decreased from 1.21~1.27 mg kg^-1to 0.29～0.30 mg kg^-1 and soil Zn from 280~311 mg kg^-1 to 196～199 mg kg^-1. But no significant change was observed in soil Pb. MC did not enhance much phytoextraction of heavy metals from the soil. Heavy metal content in the plant of S. alfredii Hance and heavy metal phytoextraction rate of the plant was not decreased with the year. Mono-cropping of S. alfredii Hance was higher in biomass production than the plant in intercropping in all the four rounds and so in total phytoextraction of heavy metals. However, in Treatment IC, the corn turned out to meet the hygienical standard for feed and even the hygienical standard for food in the fourth cropping. Calculation based on harvested S. alfredii Hance shows that the plants contributed 32.5%~36.5% to the decrease in soil Cd, while corn did only 0.47%~0.60% and the remaining 63.0%~66.9% was attributed to leaching loss `and other factors. Soil Zn was in a similar case. These findings indicate that in the studied acid soil (pH 4.7) downward leaching and S. alfredii Hance .phytoextraction both play important roles in reducing soil Cd and Zn.