Abstract: A dam safety monitoring model can provide an early warning of the monitored outliers, which helps monitor the operation status of a dam to ensure its safe operation. Based on the prototype monitoring data of a concrete dam and combined with analysis of finite element method (FEM) and traditional statistical analysis (HST), a FEM-HST hybrid prediction model of concrete dam displacement in long-term operation is developed in this paper. It calculates hydrostatic pressure components using a finite element model, and back-calculates material parameters from the monitoring data. Additionally, temperature components are calculated by a simple harmonic temperature model; time components by a linear combination model of a linear function and a logarithmic function. This hybrid model is a significant improvement on the HST model in prediction accuracy and model stability, better describing the structural and material characteristics of a dam and its foundation and better predicting its displacement under extreme loads. This helps monitor the working behavior of a dam under extreme conditions.