Abstract: Results obtained from laboratory tests of lime silt under frost and thaw cycles show that the shear strengths of lime silt and silt do not change with confining pressure. For saturated and unsaturated lime silt, their strength values are all higher than that of silt and the greater the dry unit weight is, the higher the shear strength is. The shear strength of unsaturated lime silt is greater than that of the saturated lime silt. After 1 frost and thaw cycle, the shear strength of silt has a little change, but the shear strength of lime silt is obviously lower than that of lime silt before frost and thaw cycle. After many cycles of frost and thaw, the shear strength of lime silt gradually decreases with increasing cycles of frost and thaw, and after 10 cycles, it reaches to a minimum value.