Abstract: The dynamic triaxial shear test on the dynamic properties of the Xiaolangdi in situ siltized intercalations within core samples is performed.The result indicates that shear deformation of the intercalation tends stable with the cyclic number when the total shear stress ratio α is smaller and takes a distructive trend when α is larger than 0.4 approximately .It is also found that the dynamic strength decreaes together with the cyclic number and tends to a certain value when the cyclic number attains one thousand.According to the results and the practical conditions of the Xiaolangdi dam site the values of dynamic total strength parameter are recommended.