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.　©　2016,　Beijing　University　of　Technology.　All　right　reserved.