This paper develops a promising low-priced optical fiber arcing detection system for measuring pantograph-catenary contact-loss. The system collects the ultraviolet light by UV lens. The filter cuts off visible light to reducing environmental disturbance. Ultraviolet light of arcing is transformed to visible one by fluorescent material, which is packaged on the fiber endface and has a high transforming efficiency in ultraviolet band. This optical fiber arcing detection system is equipped with self-checking pulsed light to monitoring the status of the detection system. The arcing energy is estimated by the relationship between the intensity of ultraviolet light and the output voltage signal.