A series of GDS dynamic triaxial tests under cyclic loading were carried out on the remolded loess in Haibei area in this paper. The effects of different cyclic dynamic stress and different loading frequencies on the cumulative plastic strain and stiffness degradation characteristics of the loess were studied, and the degradation model proposed by Idriss was also used in the tests. The test results show that under the same vibration times, both the cyclic dynamic stress and loading frequency have effects on the cumulative plastic strain and stiffness degradation index of the loess. Under large cyclic dynamic stress and low loading frequency, the cumulative plastic strain and the attenuation degree of degradation index of the sample are large. The degradation index decreases with the increase of cumulative plastic strain, and the attenuation degree is relatively slow under large cyclic dynamic stress and low loading frequency. The stiffness degradation index δ in double logarithmic coordinates is approximately linear with the loading vibration N, and the stiffness degradation model δ=N^-d can fit the test curve well. The correlation coefficient R² is greater than 0.9, indicating the fitting effect is good. The degradation parameter d increases with the increase of cyclic dynamic stress, and decreases with the increase of loading frequency.