Abstract: With the progress of beneficiation technology, the size of tailings is getting smaller, and the proportion of clay is gradually increasing. Therefore, it is particularly urgent and necessary to study the influences of clay content on the physical and mechanical characteristics of fine tailings. Through a series of physical and mechanical experiments, the effects of clay content on the physical characteristics, permeability characteristics, consolidation characteristics, shear characteristics and dynamic characteristics of fine tailings are studied. The test results show that as the clay content increases, C_u increases significantly, while C_c does not change significantly, and liquid limit, plastic limit and plastic index all increase. As the content of clay particles increases, the permeability coefficient decreases, and the compressibility first increases and then decreases. Cohesion keeps increasing with the increase of clay content, while the internal friction angle keeps decreasing. The effects of clay content on liquefaction of fine tailings are to promote first and then inhibit, and liquefaction damage is most likely to occur at 10%. As the clay content increases, the dynamic shear modulus decreases first and then increases, and the damping ratio increases first and then decreases. It is shown that the clay content has a significant effect on the physical and mechanical properties of fine tailings, and it should be paid full attention to in engineering.