Abstract: Redundant pump groups are widely used in various critical parts of nuclear power plants and play a vital role in ensuring nuclear safety. To enhance their reliability, this study models and analyzes the reliability of digital control of redundant pump groups under different redundancy modes. Firstly, a dynamic fault tree model of pump group failure is established based on the different operation and control logic of the digital control system for redundant pump groups under three redundancy modes. Secondly, the minimum cut-set method is employed, and a Markov model is constructed to obtain the solution approach for the dynamic fault tree under three modes. Finally, taking the digital control system for charging pumps in the RCV system of a nuclear power plant as a case study, the reliability of the system is quantitatively analyzed under the three redundancy modes. The research results indicate that, under normal operating conditions, the double hot standby redundancy mode exhibits the highest reliability for the digital control of charging pumps, followed by the cold-hot standby redundancy mode, while the double cold standby redundancy mode shows the lowest reliability. The present study provides valuable insights for improving the reliability of digital control for redundant pump groups.