Abstract: In order to further analyze the cause of coal mine accidents, explore mechanism of coal mine accidents, prevent the happening of coal mine accidents, ensure personal safety of coal mine worker, by introducing the PII analysis method, we study the necessity, feasibility of PII analysis method in coal mine accident cause analysis. Taking the actual gas accident cases, using PII analysis to analyze and research coal mine gas accident reasons from a new angle, we achieve the corresponding measures and suggestions of preventing coalmine accidents.