Abstract: In the road traffic system, the driver is the only independent variable, so the research on the changing law of the driving behavior in the car music environment has the theoretical and practical significance. According to the research results of driver's mental workload and driving behaviors in music environment, the definition of the risk of driving behavior was clarified in this paper. Evaluation on the risk of driving behavior in music environments was given by the principal component analysis and the indexes of driving behavior. Besides, the driver's heart rate variability was taken as the input and risk of driving behavior as the output, and the physiological predictor system of driver's hazard perception was established. Furthermore, the in-vehicle music listening guideline for the drivers was proposed, which could help reduce car accidents and ensure driving behavior safety.