Abstract: To reduce the risk of collision accidents between vehicles and highway guardrails, a risk assessment method for vehicle collisions with highway guardrails based on catastrophe theory was proposed. Focusing on five aspects, namely guardrails, vehicles, roads, environment, and management, the risk sources of collisions between vehicles and highway guardrails were identified; an index system with a three-level hierarchical structure was constructed, and an index evaluation model based on catastrophe theory was established. By multi-level decomposition of the evaluation targets and calculating the value of the total catastrophe membership function using a normalization formula, this method assessed the collision risk level between vehicles and highway guardrails. The example validation demonstrates that the catastrophe model can reasonably and effectively assess the target safety risk level. The assessment results are consistent with the actual situation, which provides a new idea for reducing the collision risk between vehicles and highway guardrails.