The arc voltage during the breaking process of medium and high-voltage circuit breakers is a critical parameter that characterizes arc-extinguishing performance, contact condition, and arc properties. It plays a vital role in evaluating the breaking capacity, studying arc physics, and predicting equipment lifespan. This paper proposes a non-contact online monitoring scheme for arc voltage. The proposed system comprises a dual-suspended power supply system based on a current transformer and lithium battery, an integrated self-powered and high-input impedance sensor measurement system, and an upper computer communication system. This design enables long-term reliable operation with self-powering, significantly reducing the requirements for sensor insulation and electrical installation clearance. Measurement data are transmitted wirelessly to the upper computer for reconstruction, display, and storage. Both theoretical analysis and experimental verification demonstrate that the system achieves high-accuracy and reliable arc voltage measurement while significantly simplifying installation complexity and insulation requirements. This provides effective technical support for circuit breaker condition monitoring and intelligent operation and maintenance.