With Qiaokou Town soil of Wangcheng district in Changsha City as research object, applies the single factor evaluation method and Hakansan's potential risk index to conduct the ecology risk assessment of heavy metals Pb and Cd in soil. The results show that the pollution degree of Pb to the soil in the studied area of Qiaokou Town is within the acceptable range, while the accumulation of heavy metal Cd of soil was relatively high, and the pollution is serious. The study of potential ecological risk shows that the single factor index Ei of Cd in soil is between 40~160, and Cd in the 0~20 cm soil sample is greater than 80, indicating that the element is a strong ecological danger. From the comprehensive potential ecological risk index RI, the comprehensive risk in Qiaokou Town is within an acceptable range.