Abstract: The time effect of the steel and soil interface is significant for study of the bearing capacity of the rock-socketed filling pile with steel tube. On the basis of summarizing the research findings of predecessors and by improving the indoor direct shear tests, a study is made of the shear properties of steel and soil interface which are influenced by preloading time. The preloading time is designed as 0, 1, 2, 4, 6, 17, 24 and 48 h in the tests and different preloading time is explored under the conditions of the steel-soil interface with relationships of the shear stress-strain which is affected by different normal stresses. Relationships between the shear stress and horizontal displacement, and the shear strength along with the change of interface preloading time are analyzed by the introduction of Mohr-Coulomb Failure Criterion. The shear stress is increased to a stable value with the increasing horizontal displacement; with the preloading time increasing,the friction angle and cohesive force increase, and after a certain period of time， tend to be stable. The limit of the steel-soil interface shear strength is not only related to the normal stress on the interface, but also related to the interface of the preloading time. Limiting shear stress increases with the increase of preloading time obviously; when the normal stress is lesser, the interface timing of the ultimate shear stress is more obvious.