Abstract: Dynamic strength characteristics of frozen silty clay was studied using triaxial cycle tests with the constant stress amplitude under confining pressures varying between 0.3 MPa and 16.0 MPa,at temperatures of-4℃ and-6℃ and a frequency of 2 Hz.It was shown that the dynamic strength depended not only on the number of vibrations and confining pressures,but also on loss of energy resulted from cyclic loading.According to the relationship among the dynamic strength,loss of energy and variation of temperature in specimens,an approximate formula was obtained,indicating that the loss of dynamic strength was influenced by confining pressures and the loss of energy.Thus,one of the key factors controlling the dynamic strength was the raised temperature resulted from the accumulative energy under cyclic loading.