Abstract: Accidents happened in chemical industry parks have multiple affecting factors, complex accident connecting chain nodes and uncertainty propagation paths. A method based on the complex network theory to construct the accident chain model and determine the important nodes and key accident propagation paths was proposed. Based on the relationship among the affecting factors of the accident chain, an accident chain network model of the chemical park was established. An improved TOPSIS method and weighted LeaderRank algorithm were used to calculate the key nodes of the network model. Finally, the key accident propagation path of the accident chain network based on the intensity of accident propagation was identified. The results show that the method can effectively determine the key nodes and key accident propagation paths of the accident chain network, and can provide theoretical basis for preventing accidents in chemical industry parks.