Abstract: Deformation monitoring is important for evaluating the stability of reservoir bank slopes. This paper presents an application of PSP-InSAR technology to deformation monitoring on the bank slopes of reservoirs, along with an analysis of the Changlingpi reservoir in Shenzhen using SAR data collected by a COSMO-SkyMed system during 2013-2016. In the analysis, we develop a deformation model applicable to reservoirs with time-varying levels, and make a comprehensive comparison of this model with the traditional model based on InSAR measurements, focusing on their performances in extracting bank slope information. And the deformation response of the area more significantly influenced by the variations of water level is discussed. Then, the accuracy of InSAR measurements is estimated by comparing with corresponding level measurement data, and the characteristics of the two models are further discussed. Results show that our model is capable of mining more deformation information of reservoir bank slopes from InSAR databases.