Abstract: In order to study the influence rules of clay and silt on the liquefaction resistance of sand in the mixture of clay, silt and sand, based on the static and dynamic triaxial tests, the sand specimens with two different fines (clay and silt) contents (FCs), 5% and 10%, and three different fines proportions are investigated by the static and dynamic triaxial system. The test results show that the liquefaction resistance of specimens with the same fines content and different fines proportions are different. When the fines content of the specimens is different, the laws of liquefaction resistance are different with the monotonous change of the clay or silt content in the fines. The liquefaction resistance of the specimens with FC of 10% are higher than that of the specimens with FC of 5%. The clay and silt play roles of filling, bonding and skeleton effects on the sand particles. And with the change of clay and silt content in the fines, the proportion of these three roles is different under different fines contents.