Abstract: Loop resistance of circuit breakers is a critical indicator for assessing the contact performance of the breaker; its variations directly reflect the extent of contact wear, oxidation, and burn damage. Traditional offline measurement methods fail to capture the true operating state, suffer from significant measurement errors, and exhibit high variability, rendering them inadequate for the real-time monitoring requirements of modern power systems. To address these issues, this study proposes a non-contact online monitoring system for circuit breaker loop resistance based on multi-sensor fusion. The system synergistically employs Hall-effect current sensors, infrared temperature sensors, and electric field sensors, combined with high-precision signal processing algorithms, to achieve real-time monitoring of circuit breaker loop resistance. Experimental results demonstrate that the proposed system outperforms conventional offline measurement methods, achieving a dynamic response speed of ≤200ms, measurement accuracy with errors less than 1.5%, and an anti-interference capability with an SNR exceeding 60dB. Engineering case studies have validated its practical value in fault early warning and in optimizing operational costs. This research offers a novel technical pathway for the real-time monitoring of circuit breaker loop resistance, which is of significant theoretical and practical importance for enhancing the reliability of power systems.