In order to study the effects of roughness, water content on the shear strength characteristics of silty clay-concrete interface, a large direct shear test system was developed to study the shear characteristics of silty clay-concrete interface under different roughness, water content. The results showed that the interface shear strength, interface friction angle, shear stiffness coefficient and interface residual shear stress all increase with the increase of the surface roughness of concrete, with a maximum increase of 37.0%. However, with the increase of roughness, the interface adhesion first decreases and then increases, with an increase of 23.7%. With the increase of the water content of cohesive soil, the interface shear strength, shear stiffness coefficient and residual shear stress at the interface all increase first and then decrease. There is an optimal water content between 20% and 28%, which makes the interface shear characteristics optimal. Roughness and water content have significant effects on the shear strength of silty clay-concrete interface. The test results can provide reference for the engineering practice of jacked pile.