Landslide is the second only to earthquake as one of the most serious geological hazards, which occur most frequently and cause the most serious losses. It poses a great threat to people's lives and property safety. In order to monitor dangerous landslides dynamically, GPRI-Ⅱ ground-based radar system is used in this experiment to study the key technology of landslide deformation time series analysis, and the main process of ground-based radar data time series processing is formulated. It is applied to the stability monitoring of a road slope in Shaoxing, Zhejiang Province. The experimental results show that there is an obvious deformation area in the slope, which is located in the accumulation area of the construction site, and the maximum deformation is 3.5 mm/d. At present, ground-based radar has the ability to monitor deformation with sub-millimeter accuracy when the observation conditions are satisfied. Ground-based radar has become one of the important means of disaster early warning and control.