Abstract: Based on Internet of Things technology, this article studies the intelligent monitoring system of DC system battery pack in substations, aiming to improve the safety and reliability of battery pack. Real time collection of key state parameters of batteries using wireless sensor networks, combined with Kalman filtering, fuzzy logic algorithms, and data mining techniques, for full lifecycle management and fault warning of battery packs. The experimental results show that the system can effectively improve the health status of the battery pack, reduce the failure rate, and enhance the reliability of power supply.