The Xieliupo landslide is in an active and ruptured fault zone, and its growth and movement are controlled by the active fault. Historically, the combined effect of earthquakes and rainfall has repeatedly activated the landslide, causing severe damage to life and property. Hence, it is important to evaluate the dynamic stability of the Xieliupo landslide for mitigation of the hazards. The sliding zone soil, viewed as one of the major components of a landslide, is always perceived as a key factor in keeping the landslide stable and steady. To investigate the dynamic properties of the sliding zone soil of the Xieliupo landslide, remolded specimens of various water contents are tested on a cyclic triaxial apparatus under consolidated and undrained conditions using a step-by-step method to increase the dynamic load. The test results show that the dynamic elastic modulus of the sliding zone soil decreases exponentially with the increase of shear strain under constant water content. As the water content increases, the dynamic elastic modulus of the slip soil also decreases continuously under the same confining pressure and its deterioration velocity increases with increased water content. It seems that there is a threshold water content (around the plastic limit) in describing the variation of maximum elastic modulus with water content. The maximum dynamic elastic modulus of the slip soil, calculated from the cyclic triaxial test results, initially reduces slowly with water content, but when the water content is above the plastic limit, it abruptly decreases with further increase of the water content. Additionally, the relationship between dynamic elastic modulus and dynamic strain under different water content could be perfectly normalized, referring to the maximum dynamic elastic modulus. The damping ratio of the slip soil increases with shear strain and under the same confining pressure, the damping ratio increases as the water content increases. The relations between damping ratio and dynamic shear strain of the slip soil could also be normalized based on the maximum damping ratio. Based on the analysis of the cyclic triaxial test results, it can be concluded that the backbone curves of dynamic stress against strain for the sliding zone soil of the Xieliupo landslide could be described using the conventional hyperbolic model.