Abstract: Since mine load center has such particularities as complex operating environment, intense vibration and frequent operation, the short-circuit breaking capacity of the HV vacuum switch of such load center was analyzed in detail in this paper from grid system, circuit breaker contacts, arc extinguish chamber and opening mechanism, etc. The following conclusion was acquired: the actual breaking capacity of the HV vacuum switch is less than the rated breaking capacity and will gradually decrease over time. It was proposed from the perspective of underground power supply and distribution design that attention should be paid to the scientific selection of new equipment and that the equipment in use should be supplemented by optimizing the fixed value, improving the test, strengthening the maintenance, among other measures. This proposal provides a theoretical guidance for power supply and distribution design for underground coal mine, especially for the selection of vacuum circuit breakers and the verification of breaking capacity.