Abstract: In order to study the shear properties of the interface between the sand and steel, the result of a series simple shear test and direct shear test of interface between dry, saturated sand and smooth, rough steel on the DSJ-2 electric four-joint equal stress direct shear apparatus and after reffitted is constrastively analyzed. The result shows that the shear stess-shear displacement curve of interfaces presents misalignment elastic ideal plasticity relations when the vertical stress is 50,100kPa or presents rigidity-plasticity relations when the vertical stress is 200,400kPa with the simple shear test, the shear stess-shear displacement curve of interfaces presents misalignment relations when the vertical stress is 50,100kPa or presents hyperbolic curve relations when the vertical stress is 200,400kPa with the direct shear test. In addition, the experience reduction formula of contact surface shearing strength target(the interface shear strength index with the direct shear test multiplied by a factor less than 1) are proposed to revise the direct shear test result in design.