It　is　necessary　to　ensure　the　traffic　safety　to　predict　the　driver　behavior　by　analyzing　the　physical　&psychology.　Eight　drivers　were　selected　with　age　between　35　to　48,　Electrocardiograph,　Frecord　data　collecting　system　and　dynamics　GPS　were　utilized　to　study　the　drivers＇　behavior　under　emergency　in　the　Transportation　Communication　Trial　Field.　The　mix　effect　model　between　physiology　and　braking　pedal　velocity,　which　is　affected　by　distance　between　the　vehicles　and　the　obstacle,　driving　velocity,　driving　time,　personality　and　have　influence　between　them,　has　been　established.　This　can　offer　new　method　for　the　drivers＇　behavior　analysis　under　emergency.