In the present study, the dynamic deformation characteristics of clay, including the effect of loading rate in large strain ranges, were examined by performing undrained cyclic triaxial test. The test results showed that the loading rate to failure decreased with increasing loading amplitude and decreasing loading frequency. While the stress-strain relationships was not affected by loading frequency, excess pore pressure was affected significantly with the change in loading frequency. The change for 0.1 Hz was larger for than that of 0.01 Hz, resulting in inclined effective stress paths. Furthermore, the lower the frequency was, the higher the excess pore pressure was in the first loading.