Abstract: The exploitation of the Lead and Zinc mineral resources in North Guangxi region has different degree of pollution on the red clay. In order to study the effects of lead ions pollution on the mechanical properties of Guilin red clay, the unconsolidated undrained triaxial shear tests were conducted with the different concentration at different action time under various confining pressures. The stress-strain behavior, the elastic modulus and the parameters of shearing strength were measured. The results show that: the mechanical properties of Guilin red clay are affected considerably by the concentration of lead ions, the mechanical properties of soils decreased with increasing of the concentration of lead ions, and it is the worst when the concentration of lead ions reaches the maximum(1.0%) in the test. The stress-strain curves of the red clay which was polluted by the lead ions were presented the hardening type, but its trend was decreased as the increased of the concentration of lead ions and the confining pressures. The elastic modulus, the parameters of shearing strength were decreased considerably as the increased of the concentration of lead ions, but the parameters of shearing strength show less obvious during the change of action time, which means the lead ions can finished the main damage of the structure of the soils.