Sliding friction comes into existence between soil and the surface of jaked pile during the process of penetrating.Based on the laboratory test the sliding friction and its time effect between jacked pile and soil in Tianjin Binhai New Area are studied with the improved direct shear apparatus.Angle of external friction and its law between jacked pile and soil are obtained.And the mechanism of time effect is also summarized.The results show that friction resistance is related with soil type,and is approximately linear to the vertical pressure.The increase of friction resistance between pile and clay or mud silt is proportional to the increase of carrying capacity of the pile with the time going by.It has some reference significance for the research on soil compaction effect and carrying capacity of the jacked pile in Tianjin Binhai New Area.