Abstract: With large-scale wind energy,solar energy and other new energy access to electricity,the randomness and intermittence bring great pressure to power grid dispatching and real-time balance. Pumped storage power station will play a more important role in ensuring the safe and stable operation of power grid and improving the quality of power supply. Equipment maintenance is a necessary measure to ensure the healthy operation of pumped storage units. A digital maintenance technology integrating virtual reality,intelligent decision and multiple information is proposed. A digital management system for unit maintenance of pumped storage power station is developed. The system structure and three key technologies including maintenance planning,maintenance implementation and maintenance control are introduced.Based on engineering practices,four functional modules of the system:maintenance panorama,maintenance planning,maintenance implementation,maintenance evaluation are displayed. Functions such as maintenance knowledge base construction,fine modeling,operation deduction,standardized operation,schedule control and resource prediction have been realized. Practical application shows that the system can effectively guide the maintenance of the unit,improve the quality and efficiency of maintenance operation,and save costs. The intelligent development of unit maintenance of pumped storage stations in China can also be promoted.