Order　to　solve　the　traffic　safety　problem,　this　study　is　to　identify　changes　of　drivers＇　workload　by　quantitative　measurement　of　psycho-physiological　load　based　on　psychology　and　physiologic　theory　as　they　drive　on　a　two-lane　highway　in　a　mountain　area.　The　measured　data　was　analyzed　by　using　statistics　method,　and　then　this　study　constructs　the　model　based　on　the　impact　of　the　increase　heart　rate　and　the　lengths　of　grade　and　the　average　speed　on　the　driver＇s　psychology-physiological　reaction,　the　model　was　calibrated　and　verified　by　using　real　data.　Thus　this　study　put　forward　a　new　method　for　the　research　on　traffic　safety.