The samples contaminated by heavy metal were taken from tailing pond and landfill site of wastes The different heavy metal contamination samples with different incorporation ratio are respectively mixed with the undisturbed soil. The content analysis of heavy metal, direct shear test and unconfined compression strength test are carried out in order to study the strength properties of the heavy metal pollution. The results of test and analysis show that: the heavy metal pollution has a very strong impact on the strength properties of soil. With the increase of concentration of heavy metal pollutants i, c-value gradually increased and φ value decreased. Under the same water content, the unconfined compression strength is reduced with the increase of heavy metal content. The strength will decrease by approximately 35%～60%. The characteristics of the diffuse double layer and the thickness of the water film between the soil particles will change when the heavy metal contaminants the soil, the balance relationship between cationic and anionic on the soil surface will also be broken. Therefore, the strength properties of the contaminanted soil will change.