Abstract: The authors, using the dynamic electrocardiograph, dynamic GPS and pickup camera, test the relationship between the mental tenseness of two drivers and such factors as driving speed, overtaking, etc. Through the treatment and analysis of a lot of test data, the quantitative relationship of the above factors is obtained. The result shows that without the influence of overtaking, the mental tenseness changes obviously when the driving speed is respectively at 127.4 km/h and 123.1 km / h; if there is the influence of hightailing, no obvious change takes place. At the same driving speed, the average mental tenseness under no influence of hightailing is apparently higher than that under the influence of hightailing.