Engine misfire (total or partial) causes a negative effect on the engine power and the exhaust emissions such as HC, CO and NOx. Moreover, it causes damage to the three-way-catalyst(TWC) system permanently. So, Engine misfire should be detected and eliminated.This study introduces a new system concept which is detecting combustion misfire using breakdown voltage (BDV) characteristics between electrodes. The focus of this study is that the detection and decision of misfire criterion through the misfire intensity calculation with BDV signal, which is derived by the application of a high bias voltage (30kV) to the spark-plug gap in the engine continuously. This study is driven to check the relation among BDV signal and misfire intensity inside an engine cylinder.