Abstract: In view of the fact that the indicator values are subjective and difficult to be determined accurately because of complex assessment objects and various indicator attributes in the traditional assessment methods, an interval extension evaluation method by using the interval values and the interval correlation function to determine the assessment results was proposed. The assessment index system of the emergency response capability was established according to the characteristics of chemical industry park (CIP) and the requirements of the emergency laws of China. Two-level interval extension evaluation mode was established based on extension set theory and was applied to assessing a certain CIP in Dalian city. It is shown that this method can solve the existing problem of the traditional methods and get more feasible and rational results. This work may provide a reference for the emergency management and assessment of the CIP in China.