Abstract:relative different function of the variable fuzzy theory was introduced to the building of a safety assessment model for tunnel groups. Based on the previous researches, the main factors influencing the tunnel group traffic safety were chosen to construct an evaluation index system, and then, the weights of the evaluation indexes were obtained on the basis of the results by analytic hierarchy process (AHP) method and the entropy of information. Subsequently, a relative different function assessment model was adopted to evaluate the tunnel group traffic safety level. Finally, the safety level of a mountainous freeway tunnel group in Zhejiang Province was evaluated with the proposed model, and some safety improvement measures were proposed accordingly. A comparative study of the analytical results show this model is effective in traffic safety assessment for tunnel groups on freeways.