Abstract: To explore and predict the unsafe lane-changing behavior of drivers in tunnels, a structural equation model of lane-changing behavior of drivers in tunnels was established based on the extended theory of planned behavior（Ex-TPB） by introducing driving habit explanatory variables on the theory of planned behavior. A questionnaire survey was conducted among drivers. Based on 321 questionnaires data, the effectiveness of the structural equation model was analyzed, and from psychology, the psychological factors on driver lane-changing behavior and the relationship among various factors were analyzed. The results show that the structural equation model is suitable for analyzing the lane-changing behavior of drivers in tunnels. Driving habits, lane-changing behavior intention and perceived behavior control have direct positive and significant effects on lane-changing behavior. Driving habits, behavioral attitudes and perceived behavioral control have significantly positive effects on lane-changing behavior intention, while subjective norms have significantly negative effects on lane-changing behavior intention.