Abstract: A vast number of cases have demonstrated that a major disaster can trigger a series of secondary disasters, forming a disaster chain with much more destructive power than a single-type disaster. Understanding the process of disaster chain formation and establishing a conceptual model for risk assessment are the premise for governance of the disaster chain risk. In this paper, we first reviewed the chain risk assessment models from the studies at home and abroad, e.g., the accident chain, supply chain and so on, and then, taking Wenchuan Earthquake as a case study, we proposed a new conceptual model of disaster chain risk assessment. The two major conclusions are: (1) sensitivity of the environment susceptible to disasters is an important impact factor, which determines the probability of disaster chain. Therefore, the key aspect of risk assessment is to identify the factors affecting the sensitivity of the environment and characterize their quantitative relationships. (2) Vulnerability of a disaster-affected area in a disaster chain increases after incurring repeated hazards; evaluation of change of the vulnerability of the area will improve the precision of disaster chain risk assessment. This study aims to improve the theory on disaster system research and provide a basis for further improvement of disaster chain risk governance.

Key words: conceptual model, disaster chain, risk assessment, Wenchuan Earthquake