Abstract: This paper systematically researches the core application of key power system automation technologies (SCADA, DCS, EMS, DMS) in power grid operation and management. Through the construction of wide-area real-time sensing network, closed-loop control system and intelligent decision-making platform, the automation technology realizes precise monitoring of grid operation status, rapid self-healing of faults, optimal scheduling of resources, and collaborative management of source-network-load-storage. The study shows that: SCADA system relies on state estimation to provide panoramic operational situational awareness and support remote intensive control; DCS guarantees rapid response of power generation units to dispatching instructions through hierarchical step structure; EMS drives economic dispatching under security constraints based on optimal trend model; DMS significantly improves power supply reliability by using feeder automation and voltage reactive power optimization. Automation technology has become the core pillar for building a safe, efficient and intelligent modern power.