Miniature circuit breaker has been frequently applied in domestic areas and similar places, so how to safely use miniature circuit breaker is of great significance. And circuit always appear the accident situation such as short circuit, overload, therefore requires and miniature circuit breaker at the break. If small circuit breaker and timedivision, high short circuit current will cause fever, such as welding phenomena of the miniature circuit breaker, and damage to equipment at a lower level. This article mainly analyse the reason of breaking and miniature circuit breaker, switching angles in the research process of breaking the joule integral effects, on the impact of miniature circuit breaker tripping situation. To better protect small circuit breaker and at a lower level equipment. For circuit fault occurs at home and abroad of miniature circuit breaker breaking current value its influence factors are studied, under what conditions for research of miniature circuit breaker tripping device tripping, both at home and abroad for its different breaking current generated by the test.