Abstract：Based on a lot of dynamic triaxial tests，some dynamic characteristics on roadbed compaction loess are studies. It is indicated that from test results，the relation between stress and strain can be fitted with hyperbolic model under certain conditions，and the values of model parameters are and tend to be stable gained on some soil samples. Dynamic modulus of compaction loess decreases with the increase of dynamic strain，the trend is basically similar under different dry densities，water contents and pressures. Damping ratio is affected by the moisture，consolidation stress ratio，confining pressure and dry density of the compacted loess which increases with the increase of dynamic strain generally；and its value is distributed in 0.2–0.3 with high discreteness. The value of vibration deformation has important relation with the dry density，moisture and load cyclic number. When the dry density increases，moisture decreases，and load cyclic number increases. It decreases slowly at the same stress conditions，and there is critical dynamic stress. When the dynamic stress is smaller than it，vibration deformation is small and can be fitted linearly with the dynamic stress，otherwise，it increases quickly and presents obvious non-linearity.
