Abstract: Based on applied theories of traffic engineering psychology,the paper aims to quantitatively analyze highway landscape's effect on driving behavior based on drivers' physiological performance,and quantify highway length thresholds under three typical landscape patterns,namely “open”,“semi-open”and “vertical”ones. These studies were designed in the combination of the driving-simulator studies with the field operational tests for verification. And devices utilized here were the driving simulator,and electrocardiograph. Specifically, vehicle-related data, ECG data and supplemental subjective stress perception were collected. The evaluation results extrapolated the drivers ' U-shaped physiological response to landscape patterns. Models on highway length were built based on LF / HF's variation trend with highway length. The results reveal that the theoretical highway length threshold tends to increase when the landscape pattern was switched to open,semi-open and vertical ones. The reliability and accuracy of the results is validated by questionnaires and field operational tests. With precision rates of theoretical thresholds higher than 90%,the model results were testified to have had high reliabilities.