Abstract: To explore the research status of the complexity mechanism of hazardous chemical road transportation accidents, a new literature classification method based on accident risk characteristics is proposed. This method comprehensively evaluates existing literature from four aspects: complexity and complex system characteristics, accident causation theory, accident risk evolution process, and accident risk coupling consequences. The analysis show that in the past two decades, research related has developed rapidly, with the most mature research on accident causation theory. The evolution of accident risk and the coupling of accident risk are gradually becoming the focus of scholars' attention; Most research focused on the macro level, with relatively little research on the micro level. A complete theory hasn't been formed on how risks and energy are transmitted and transformed at different levels, nor has the process and laws of the interaction and evolution of internal risk factors within the system been revealed; Based on new classification methods, it has been found that most studies use single objective solving or multi-objective optimization models, which fail to fully consider the dynamic risk characteristics and time-varying effects of transportation processes. Accident uncertainty analysis based on accident consequences and environmental pollution risks may be a future hotspot.

Key words: hazardous chemicals; road transportation; accident complexity; causal theory; risk evolution; risk coupling