In order to enhance emergency response capability to deal with emergencies， power enterprises compile more perfect emergency plans. Based on the method of ontology， the emergency plans with text format are transformed to the formal language understanding by computer， and the decision references in emergency response are extracted. Moreover， the mathematical model of emergency aid decision rules is built. Based on the classic Apriori algorithm， a power emergency decision support rules generation method is proposed. Taking a power company's emergency plan as an example， the actual effect of the generation method is analyzed， which builds the foundation for further research on dynamic generation of strategy about emergency damage restoration control and emergency resource scheduling.