The specific on-site environment of the mining industry field puts forward higher request to the safe operation of electrical equipment. Especially the arc-fault is one of the most important causes of disasters in distribution system. The traditional methods of the arc-fault detection and protection are based on the extraction and diagnosis of the single signals such as electric current, voltage, arc light, etc. Though the combined methodology has been proposed, it is difficult to implement and the cost is increased. On the basis, a double-criterion monitoring and protection method is proposed, which takes both electric current and arc light as the monitoring parameters. By use of the sensing measures of photosensitive dynatron matrix and expert system evaluation method, arc-fault in the high-voltage switch cabinet can be effectively judged and located and the fault can be cut timely, then the service life and safety and reliability of switch apparatus can be enhanced, ensuring the safe and stable operation of the mining power system.